Put inside trendy group (5)
I believe the answer is:
inset
'put' is the definition.
Although both the answer and definition are singular nouns, I can't understand how they can define each other.
'trendy group' is the wordplay.
'trendy' becomes 'in' ('in' can mean fashionable).
'group' becomes 'set' (both can mean a collection).
'in'+'set'='INSET'
'inside' acts as a link.
Can you help me to learn more?
(Other definitions for inset that I've seen before include "Thing inserted" , "Reduced image" , "Page within a page" , "Small diagram contained by larger one" , "Training during term time for teachers in state schools" .)