Green’s Dictionary of Slang

(US) a member of the Teamsters’ Union.

1930		‘Dean Stiff’ Milk and Honey Route 24: The rawjawed teameos and muckers, dynoes and shantymen who built that railroad.
1930		J. Lait Gangster Girl 43: He works through a flock o’ tough teamios.
1934		(con. 1920s) J.T. Farrell Young Manhood in Studs Lonigan (1936) 337: I was thinking what would the teameos I know at the express company think if they knew I was going to a Y.M.C.A.