Green’s Dictionary of Slang

a dinner jacket.

1961		M. Terry Old Liberty (1962) 36: I bought myself a penguin suit.
[1962		P. Crump Burn, Killer, Burn! 158: ‘Say, Deacon, ya cop a tux?’ Earl asked. ‘What de hell do I look like, a penguin?’].
1969		N. Cohn Awopbop. (1970) 11: The big bands lined up strict and formal in penguin suits.
1975		‘P.B. Yuill’ Hazell and the Three-card Trick (1977) 90: I’d just been one of the flunkeys in penguin suits.
1977		B. Humphries in Tharunka 13 June 14/4: ‘[A]ll you gotta do is to front up in your penguin gear on the first nights of the Australian Dried Fruit Ballet Awards’.
1983		M. Read Scouting for Boys in Best Radio Plays (1984) 168: You don’t know where you are without me, do you comrade? I ain’t wearing that penguin suit no more.
1985		B. Humphries Traveller’s Tool 31: If you like getting into penguin gear, watch out for the sub-tropical weather.
1997		J. Birmingham Tasmanian Babes Fiasco (1998) 110: I recognise that fucking penguin suit.