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.
Armor
Armor: An isolated, static ability that means, "This unit can only be hit on a roll of 5 or more." Armor works against dice of damage and attack dice. It redefines what die roll is required to hit a unit. It doesn’t modify the die roll like Accuracy. A unit with Accuracy 1 attacking a unit with Armor hits with 4's, 5's, and 6's.
Bombard
Bombard X: A cumulative, static ability that means, "This unit may attack a unit in the Ground arena instead of the Space arena, using X power plus any other effects." You choose whether to use Bombard to attack a unit in the Ground arena or to make a normal attack in the Space arena. You can't attack a unit in the Space arena using Bombard. Power changes affect Bombard.
Bounty
Bounty: [bonus]: A layered ability triggered during a unit discard that means, "When another unit is discarded by damage from this unit, you gain the following when your next build step starts." Bounty triggers even if the attacking unit leaves play. Bounty works in the build zone. You will gain the bounty even if the attacking unit is sent to the discard pile. The unit can't collect a bounty on itself.
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.
Deflect
Deflect X: A layered ability activated during the damage prevention POP that means, "Prevent X damage to this unit, and this unit may do that much damage to a unit of your choice in the same arena." Deflect creates new damage that can be done to any unit in the arena (even itself). Deflect may be deflected any number of times. Damage is applied after all prevention and deflects resolve. The damage that the unit does equals the damage it prevented. You can play each Deflect effect only once for each source of damage. Deflect as much damage as you can up to the Deflect value.
Enhance
Enhance: [Effect]: A selective, static effect that means, "You may play the following effect by paying the additional cost." The effect states whether you play it "instead" or "also". You must declare it to get its effect.
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.
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.
Parry
Parry X: A cumulative ability triggered during the damage prevention POP that means, "If the attacking unit rolled at least one natural '1' against this unit, prevent X damage to this unit." Only one natural "1" is counted from the attack roll after re-rolls. Parry doesn't prevent damage from a parrying unit unless it attacks itself. Parry can't affect unpreventable damage. If a unit gets the Parry ability after you roll attack dice, it's too late to affect the damage. Accuracy can't decrease the die roll to a natural "1". However, you or your opponent may use an effect to re-roll dice to affect the number of natural ones. (You only count the 1, if any, from the roll used for the attack.) Parry applies only to dice rolled for an attack, not to dice rolls for abilities like Retaliate.
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.
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.
Stealth
Stealth: An isolated, static ability that means, "This unit can't be attacked unless it's tapped or has damage counters on it." An untapped and undamaged unit with Stealth can still be affected by alternative types of damage. (Such as Overkill.) As long as the unit has any number of damage counters on it, it can't use Stealth.
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.