Like the hair of the dog with a silly tail? (5)
I believe the answer is:
curly
'a silly tail?' is the definition.
Both the answer and definition are adjectives. Perhaps you can see an association between them that I don't see?
'like the hair of the dog' is the wordplay.
I cannot quite see how this works, but
'like' could be 'ly' (similar in meaning) and 'ly' is present in the answer.
'dog' could be 'cur' (a cur is an aggressive or scruffy dog) and 'cur' is located in the answer.
This accounts for all the letters.
This explanation may well be incorrect...
'with' acts as a link.
Can you help me to learn more?
(Other definitions for curly that I've seen before include "Permed" , "Like a pig's tail" .)