Green’s Dictionary of Slang

hollow leg n.

also hollow legs

1. (orig. US, also glass legs) a capacity for heavy drinking, a heavy drinker; occas. of over-eating.

[US](con. 1918) E.W. Springs Rise and Fall of Carol Banks 253: Does he drink? Does he! [...] He’s got a hollow leg.
[US]A.J. Pollock Und. Speaks 46/1: Glass legs, a person who can consume a large quantity of liquor without displaying any ill effects.
[US]W.D. Overholser Buckaroo’s Code (1948) 113: His appetite grew until Santiam said, ‘You sure got a hollow leg’.
[US]B. Appel Tough Guy [ebook] ‘He was a drinker [...] He had hollow legs’ .
[Aus](con. 1964-65) B. Thorpe Sex and Thugs and Rock ’n’ Roll 31: I was a fat little fuck but I learned how to eat! I swear it gave me hollow legs.
[US]E. Bunker Mr Blue 119: It was a boozy time, and lots of Marion’s friends had hollow legs.
B. Armstrong ‘God Bless the Aussies’ at 🌐 The Aussies don’t take prisoners. Their idea of how to end an enjoyable evening was a free ride back to their boat in a shore patrol wagon. [...] All of them had hollow legs and a camel’s thirst.

2. a person who can indulge to a great extent.

[US]E.P. Norwood Other Side of the Circus 50: Mister Willie Hollow-legs Carr [...] who can see the flag farther and eat more than any agent ahead of the show.
[UK]I. & P. Opie Lore and Lang. of Schoolchildren (1977) 187: They call him [...] hollow legs.