not have enough sense to pour piss out of a boot, v.

not have enough sense to pour piss out of a boot v.

also ...to pour piss out of a tin can

(US) to be very stupid.

1954		(con. 1920s–30s) J.O. Killens Youngblood (1956) 134: Old man Mulberry didn’t have sense enough to pour piss out of a tin can.
1971		R.D. Pharr S.R.O. (1998) 118: ‘To look at him you wouldn’t think he had sense enough to pour piss outa a boot’.
1977		Maledicta 1 (Summer) 13: He is so dumb he couldn’t pour piss out of a boot-with the directions printed on the heel.
1988		(con. 1930s) C.E. Lincoln The Avenue, Clayton City (1996) 147: A po’-ass cracker too dumb to pour piss out of a boot.