Wiktionary
budgie smugglers
alt. (context Australia NZ informal plural only English) A style of tightfitting men's swimming costume cut like underwear briefs that covers the buttocks and groin but not the legs, especially worn in surf lifesaving and in swimming races. n. (context Australia NZ informal plural only English) A style of tightfitting men's swimming costume cut like underwear briefs that covers the buttocks and groin but not the legs, especially worn in surf lifesaving and in swimming races.