Clothes fastener (3)
(Other definitions for peg that I've seen before include "Brandy and soda drink measure" , "Old song: ''... o' my heart''" , "Wooden pin, small marker" , "Clip for hanging washing" , "that may have hat or coat on" .)
(Other definitions for popper that I've seen before include "providing drug" , "2 [PHILOSOPHER]" , "Press-stud" , "making reports?" , "Press stud" .)