Squander in bigtop depression? (4)
I believe the answer is:
blow
'squander' is the definition.
(synonyms)
'bigtop depression?' is the wordplay.
'bigtop' becomes 'b' (top of the word 'big').
'depression?' becomes 'low' ('low' can be a synonym of 'depression').
'b'+'low'='BLOW'
'in' is the link.
(Other definitions for blow that I've seen before include "fluff" , "haymaker, perhaps" , "cocaine from US" , "Use pipe for" , "'..., ..., thou winter wind' (As You Like It)" .)