Accuracy X/-X: A cumulative, static ability that means, "Add X to each of this unit’s attack dice." and "Subtract X from each of this unit’s attack dice." respectively. Accuracy can’t alter "natural" rolls to affect Critical Hit, Fury, or Parry, but it can affect your chance against Armor. If a unit gets the Accuracy ability after you roll attack dice, it's too late to affect the hits.
Avenge
Avenge X: A cumulative, triggered ability that means, "Whenever damage from an attacking unit causes one of your other units in the same arena as this unit to be discarded, this unit does X dice of damage to the attacking unit when the attack ends."
Critical Hit
Critical Hit X: A cumulative ability triggered during the pending damage POP that means, "If you rolled at least one natural six with this unit's attack dice, this unit does X more damage for this attack." Only one natural "6" counts in the attack roll after re-rolls. If a unit gets the Critical Hit ability after you roll attack dice, it's too late to affect the damage. Accuracy can't increase the die roll to a natural "6". However, you or your opponent may use an effect to re-roll dice to affect the number of natural sixes. (You only count the six, if any, from the roll used for the attack.) Critical Hit applies only to dice rolled for an attack, not to dice rolls for abilities like Retaliate.
Equip
Equip: A selective effect on Equipment activated during the build step that means, "Attach this Equipment to a unit. Play only during your build step." You can pay the Equip cost only once per turn.
Evade
Evade X: A layered ability activated during the damage prevention POP that means, "Prevent up to X damage to this unit." You can play Evade only once for each instance of damage. You don't have to use all of the Evade. You choose how much damage to Evade up to X, even if the full amount of damage or more is pending.
Foresight
Foresight: [Effect]: A static, layered effect that means, "Whenever this unit attacks, you may predict the number of hits that will be rolled for that attack. If you're correct, gain the [effect]." For example, a unit with "Foresight: Gain 2 Force" will give you 2 force if you guess the number of hits rolled correctly.
Forewarning
Forewarning: [Effect]: A static, layered effect that means, "Whenever this unit is attacked, you may predict the number of hits that will be rolled for that attack. If you're correct, gain the [effect]. For example, a unit with "Forewarning: Gain 2 Force" will give you 2 Force if you guess the number of hits rolled correctly.
Hidden Cost
Hidden Cost X: A selective, static effect that means, "As long as you have a number of build counters on this card equal to X or the unit's current build cost (whichever is less), you may complete it anytime by paying Force for the remaining build cost, if any." Effects and stacking rules may reduce the build cost. You do not need to pay Force if the build cost is within the Hidden Cost integer. You can deploy it to the build zone. Hidden cost can only be played if the card is partially built and has the required number of build counters on it. You may use Hidden cost anytime, even during any Play-or-Pass chances not reserved for re-roll, damage prevention, or disrupt POP chances. If there are a number of build counters on the unit equal to or greater than the Hidden Cost integer, you do not need to pay any Force. You may not use Hidden Cost to deploy a Pilot to a unit.
INSERT
INSERT: A layered, static ability that means, "When this card is in play or stacked under the unit, the unit gets the following effect:" Insert works while in the build zone. The effect works while anywhere in the unit's stack. The granted ability remains to be the ability of its type. (For example, activated abilities granted by Insert may be disrupted.) The granted effect may not work in the build zone as per the rule for the rule for that effect.
Lucky
Lucky X: A cumulative, static ability that means, "Each time this unit attacks or is attacked, you may re-roll up to X of this unit's attack dice or have your opponent re-roll up to X attack dice against this unit." Both players can use Lucky effects according to the rules for POP chances. Lucky is used only once after all triggered re-roll effects resolve. You can't re-roll more dice than are rolled for the attack. You may choose to roll any number of dice up to the Lucky value.
Meditate
Meditate: An isolated effect activated during a POP chance or your build step that means, "You may play this card from your discard pile without paying the printed cost. Play only during a POP chance or during your build step. When this card would be discarded, remove it from the game instead." Meditate can only be activated when the card is in your discard pile. Paying the Meditate activation cost means you don't pay the normal printed cost of the card.
Overkill
Overkill: An isolated ability triggered during the pending damage POP that means, "When this unit attacks, you may divide hits in excess of the defending unit's remaining health between that unit and another unit in the same arena." The player who controls the attacking unit decides how many hits (if any) in excess of the defending unit's remaining health to reassign as damage to the second unit. (That player can't change their mind afterward.) A number of hits equal to the defending unit's health must be assigned to the defending unit, and the remainder may be assigned to the defending unit or another unit in the same arena. Overkill damage is caused by the ability, not the die roll. Shields, Parry, and Armor have no effect against it, but damage prevention not specifying dice works normally. Both units resolve damage in tandem.
Pilot
[sub-type] Pilot: A layered, static ability written as "[sub-type] Pilot. The [sub-type] gets:… ." that means, "You may move this card onto or off of a non-Droid Space or Ground unit of the correct sub-type once during the build step. Ignore all other text on this card except its name, sub-type and health. The piloted unit can't have more than one Pilot." Treat all of a unit's Pilot abilities for a sub-type as a single Pilot ability for that sub-type. It grants abilities to that unit alone. See the "Pilots" section of the rules PDF for more info.
Protect
Protect X: A layered ability activated during the damage prevention POP that means, "Prevent up to X damage to one of your other units in this arena." You can play Protect only once for each instance of damage. You don't have to use all of the Protect. You choose how much damage to Protect up to X, even if the full amount of damage or more is pending.
Retaliate
Retaliate X: A layered ability activated during the attack POP that means, "If a unit in the same arena as this unit is attacking this unit, this unit does X dice of damage to that unit when the attack ends." A Retaliate ability without an activation cost has a printed cost of "Pay 0 Force -->". Retaliate resolves when the attack ends, even if your unit gets discarded. Retaliate dice are just dice of damage, not attack dice, and can trigger Stun. Retaliate based on a unit’s power is based on its total power at the time the Retaliate is activated. Retaliate doesn't work with attacks from another arena (such as Bombard and Ion Cannon) or the build zone. A unit may retaliate against itself if it attacks itself. Each Retaliate may be used once per attack. Each defending unit can activate Retaliate during the attack POP, which resolve in their order when the attack ends, even if the retaliating unit is discarded.
Shields
Shields X: A cumulative, static ability that means, "The attacking unit gets –X power against this unit." Shields only matters when attack dice are rolled. If you give a unit Shields after your opponent has rolled for damage, it doesn't affect the roll.
Stack
Stack: [List]: A layered, static ability that means "You may put a listed card under this unit as part of its stack." The listed cards can't be on top of the stack. Cards with the Stack ability don't count as the cards listed and don't contest with any of the listed cards. If a card is listed by its name you can't stack a card with a different name unless it satisfies a different criteria in the [list] or they represent the same unit. (See the "Different Versions with Different Names" section in the rules PDF) Unlike a normal stack, you can only have one version of each unique unit from the [list] in the stack. Non-unique cards listed on a card with the Stack ability are permitted to form a part of the stack and you can have multiple cards with the same name in the stack as long as they are non-unique. Cards added to a card's stack using the Stack ability cannot exceed the 4 card maximum normal stacking rule. If a unique card with the Stack ability has another version of itself move to the top of it's stack, discard any cards in the stack that can't stack with the new version on top of the stack.
Stun
Stun X: A cumulative ability triggered during the damage placement POP that means, "When this unit damages another unit, that unit gets –X power until end of battle." If no damage counters are placed as a result of damage, Stun doesn't occur. Stun works anytime the unit damages another unit, not just when it attacks. Only the unit with both Deflect and Stun abilities can stun when it activates its Deflect.