Puppy needs assistance after start of winter (5)
I believe the answer is:
whelp
'puppy' is the definition.
(thesaurus)
'assistance after start of winter' is the wordplay.
'assistance' becomes 'help' ('help' can be a synonym of 'assistance').
'after' is a charade indicator (letters next to each other).
'start of' indicates taking the first letters.
The first letter of 'winter' is 'w'.
'help' put after 'w' is 'WHELP'.
'needs' acts as a link.
(Other definitions for whelp that I've seen before include "impudent young lad" , "Puppy- young wolf" , "Puppy, cub" , "Produce issue" , "Offspring of wolf" .)