Mock light with ring attached (7)
I believe the answer is:
lampoon
'mock' is the definition.
(I've seen this before)
'light with ring attached' is the wordplay.
'light' becomes 'lamp' (lamp is a kind of light).
'with' means one lot of letters go next to another.
'ring' becomes 'O' (letter resembling a ring).
'attached' becomes 'on' (I've seen this in other clues).
'lamp'+'o'+'on'='LAMPOON'
(Other definitions for lampoon that I've seen before include "Piece of writing that ridicules someone" , "Burlesque" , "Literary satire" , "Parody" , "Personal satire" .)