We are ready to invade enemy territory.

We are conducting training to devise strategies against hypothetical enemies.

The enemy general is approaching our camp.

Enemy troops are approaching our position.

He experienced his first encounter with the enemy on the battlefield.

He encountered the enemy on the battlefield.

His grandfather was a member of the special attack squad.

He said, 'It's difficult to make a life,' explaining the phrase 'When a man steps over the threshold, he has seven enemies.'