Green’s Dictionary of Slang

1. to fail.

1927		W.R. Morse ‘Stanford Expressions’ in AS II:6 277: poop out—fizzle.
1938		Democrat-Argus (Caruthersville, MO) 26 July 7/5: We knew the republicans were getting pretty low on material, but never realised they had pooped otu to that extent.
1944		‘Jiver’s Bible’ in D. Burley Orig. Hbk of Harlem Jive.

2. to have a breakdown; mental or physical; also of a machine, to go wrong.

c.1935		‘William Powell and Myrna Loy in “Nuts to Will Hays”’ [comic strip] in B. Adelman Tijuana Bibles (1997) 88: Just as I get warmed up, you poop out!
1948		(con. 1944) N. Mailer Naked and Dead 502: I’m sorry I pooped out yesterday.
1960		J. Havoc Early Havoc 85: ‘Looka him [...] poopin’ out again’.
1965		(con. 1930s) R. Wright Lawd Today 150: Two hours is enough to poop you out!
1971		B. Malamud Tenants (1972) 4: If it pooped out, and it pooped often – the furnace had celebrated its fiftieth birthday – you called the complaint number.

3. to die.

1935		(con. 1920s) J.T. Farrell Judgement Day in Studs Lonigan (1936) 768: Get killed under a train [...] or just poop out with heart failure.
1974		J. Lahr Hot to Trot 139: I was thumbing through the yearbook [...] So many of the Class of ’Thirty-six pooped out – drunkards, playboys, suicides.

4. to faint; to collapse; to be excessively drunk.

1962		S. Longstreet Flesh Peddlers (1964) 159: Was I bad again last night? After I pooped out?
1969		B. Beckham My Main Mother 35: He poops out early, gets tired very quickly.