Skimpy garment all the rage? Nonsense! (3,5)
I believe the answer is:
hot pants
'skimpy garment' is the definition.
(I've seen this before)
'all the rage? nonsense' is the wordplay.
'all the rage?' becomes 'hot' (I've seen this in another clue).
'nonsense' becomes 'pants' (I can't explain this - if you can you should give a lot more credence to this answer).
'hot'+'pants'='HOT PANTS'
Can you help me to learn more?
(Other definitions for hot pants that I've seen before include "Skimpy garment" , "revealing attire" , "These highlight bottom" , "Brief skin-tight shorts worn by young women" , "Women's very brief shorts" .)