Enemy (3)
'enemy' is the definition.
(synonyms)
This is all the clue.
(Other definitions for foe that I've seen before include "Adversary" , "Environmentalists" , "Antagonist" , "opposing side" , "Opposition" .)
'enemy' is the definition.
(I've seen this before)
This is the entire clue.
(Other definitions for adversary that I've seen before include "Enemy or rival" , "Antagonist, opponent" , "Foe, opponent" , "Opponent or enemy" .)