Green’s Dictionary of Slang

(US tramp) a frequenter of a tramp encampment.

1918

H. Simon ‘Prison Dict.’ in AS VIII:3 (1933) 28/2: JUNGLER. Habitue of the jungles, a hobo who through sloth or decrepitude prefers to live in the jungle, occasionally begging or doing odd jobs in town, rather than to keep on the bum.