Modify some liberal terms (5)
I believe the answer is:
alter
'modify' is the definition.
(I know that modify can be written as alter)
'some liberal terms' is the wordplay.
'some' indicates a hidden word (some of the parts of the word are used).
'ALTER' is hidden in the letters of 'liberal terms'.
(Other definitions for alter that I've seen before include "and 10 Across: Second self" , "Revise" , "Change, maybe later" , "Make changes to" , "Adapt" .)