Crowds seeing run in skimpy underwear (7)
I believe the answer is:
throngs
'crowds' is the definition.
(thronging is a kind of crowding)
'run in skimpy underwear' is the wordplay.
I cannot quite see how this works, but
'run' could be 'r' (cricket abbreviation) and 'r' is found within the answer.
'underwear' could be 'thong' (I have seen 'Skimpy underwear' mean 'thong' so perhaps 'underwear' could also mean 'thong') and 'thong' is found in the remaining letters.
A single letter 's' remains which might be clued in a way I don't see.
This may be the basis of the clue (or it may be nonsense).
'seeing' acts as a link.
Can you help me to learn more?
(Other definitions for throngs that I've seen before include "Crowds" , "Lots of people" .)