Men's pants (1-6)
I believe the answer is:
y-fronts
'men's pants' is the definition.
(I've seen this before)
This is all the clue.
(Other definitions for y-fronts that I've seen before include "Male undergarment" , "Underwear (of a certain character?)" , "Pants for men" , "Type of underpants" , "Men's pants" .)