Was an informer like a lawn? (7)
I believe the answer is:
grassed
'was an' is the definition.
I can't judge whether this defines the answer.
'informer like a lawn?' is the wordplay.
'informer' becomes 'grass' (grass can mean an informant).
'like a lawn?' becomes 'ed' (I can't justify this - if you can you should believe this answer much more).
'grass'+'ed'='GRASSED'
Can you help me to learn more?
(Other definitions for grassed that I've seen before include "Gave away information" , "catch thus dropped" , "Turfed - informed" , "green?" , "Snitched, shopped" .)