conk

2
[ kongk, kawngk ]
/ kɒŋk, kɔŋk /

verb (used without object) Slang.

to break or fail, as a machine or engine (often followed by out): The engine conked out halfway there.
to slow down or stop; lose energy (often followed by out).
to go to sleep (usually followed by off or out).
to lose consciousness; faint (usually followed by out).
to die (usually followed by out).

Origin of conk

2
First recorded in 1915–20; perhaps of imitative orig.

British Dictionary definitions for conk off

conk
/ (kɒŋk) slang /

verb

to strike (someone) a blow, esp on the head or nose

noun

a punch or blow, esp on the head or nose
the head or (esp Brit and NZ) the nose

Word Origin for conk

C19: probably changed from conch