Less well entertained by some light banter (8)
I believe the answer is:
raillery
'banter' is the definition.
('raillery' can be a synonym of 'banter')
'less well entertained by some light' is the wordplay.
'less well' becomes 'iller' ('ill' can be the opposite of 'well' so perhaps 'iller' is reasonable for 'less well').
'entertained by' indicates putting letters inside (I've seen this in other clues).
'some light' becomes 'ray' (ray is a kind of light).
'iller' going inside 'ray' is 'RAILLERY'.
(Other definitions for raillery that I've seen before include "Playful satire" , "Good-humoured teasing" , "(Example of) banter" , "Satirical banter" , "Banter, back-chat" .)