Making fun of age isn't wrong (7)
I believe the answer is:
teasing
'making fun of' is the definition.
(I've seen this before)
'age isn't wrong' is the wordplay.
'wrong' is an anagram indicator.
'age'+'isnt'='ageisnt'
'ageisnt' with letters rearranged gives 'TEASING'.
(Other definitions for teasing that I've seen before include "Making fun of in a playful way" , "Tantalising" , "Playfully ragging" , "Vexing playfully" , "Making fun of (someone)" .)