Wife gives aid to impudent youths (6)
I believe the answer is:
Here is my best explanation:
'impudent youths' is the definition.
'wife gives aid to' is the subsidiary indication.
'wife' becomes 'w'.
'gives aid to' becomes 'helps' (helping is a kind of giving aid to).
(Other definitions for whelps that I've seen before include "Gives birth", "Young wolves or dogs", "gives birth", "puppies" and "Young dogs or pups".)