You took every precaution, but we're up against a diabolically clever enemy.
It's a cinch we're up against a clever and highly scientific enemy.
That man was one of his cleverest enemies.
What would be the point of cyphering messages that very clever enemies couldn't break?
How can I guard against the clever enemy, sensei?
The Emperor is a very clever and dangerous enemy.
What if the pollution were caused at long range by a clever enemy?
Making dumb mistakes which, if they were made in combat, would lead to gaps that a clever enemy could exploit.
There were signs of a ruthless, clever enemy behind all of this.
Molydei are strong and clever enemies, feared also by other demons.