Unit Attributes
Attributes are the innate, "passive" abilities that units can use. As such, they do not have to be activated, although they may bestow an ability that can be activated:
Stalk
Units that have the stalk attribute can walk whilst hidden on any terrain.
Snipe
Units that have the snipe attribute can fire whilst hidden.
Mount/Dismount
Some cavalry units can dismount and remount during battle. If their horses subsequently take casualties they will all run from the field.
Place Stakes
A unit with the place stakes attribute will have the stakes ability. It cannot be used during deployment.
Hide (Woodland)
Units that have the hide (woodland) attribute can hide in woods and forests.
Hide (Scrub)
Units that have the hide (scrub) attribute can hide in scrubland and deep vegetation.
Hide (Long Grass)
Some units can hide in long grass only.
Immune to Attrition
Units with this ability will not suffer from attrition on the campaign map. This tends to be reserved for highly-disciplined elite units.
Disciplined
A disciplined unit has high morale that cannot easily be shaken.
Impetuous
An impetuous unit may break formation and attack without orders. The more disciplined or elite a unit is, the less likely this is to happen.
Inspire
Some units can boost the morale of other units positioned close to them.
Resistant to Fatigue
A unit that is resistant to fatigue will take longer to tire battle.
Siege Ladders
All non-cavalry units can scale walls with siege ladders.
Climb Fast
Units that have this attribute can use climbing claws to scale walls quickly.