Seemingly self-contradictory statement (7)
I believe the answer is:
paradox
'seemingly self-contradictory statement' is the definition.
(I've seen this before)
This is the entire clue.
(Other definitions for paradox that I've seen before include "Ambiguity" , "A statement that seems to contradict itself" , "Apparently contradictory statement" , "self-contradiction" , "Absurd or self-contradictory statement" .)