The rules that use the vocabulary item "enemy" are:

<enemy_noun>

enemy

enemy ambush

enemy ambush in place

enemy firing position

enemy infantry firing position

enemy infantry position

enemy position

enemy unit

enemy units

enemy vehicle

enemy vehicles

<force>

enemy

<enemy_noun-mobile>

enemy

enemy unit

enemy units

enemy vehicle

enemy vehicles

<action_word>

enemy

enemy ambush

enemy unit

<location_noun>

enemy position