So-called man-lion hybrid (7)
I believe the answer is:
nominal
'so-called' is the definition.
(I've seen this before)
'manlion hybrid' is the wordplay.
'hybrid' indicates anagramming the letters (a hybrid is a mixture).
'manlion' with letters rearranged gives 'NOMINAL'.
(Other definitions for nominal that I've seen before include "In name or form only" , "Existing in name only" , "Inconsiderable" , "Trivial" , "Ironical understatement (gram mar.)" .)