whodunit

[ hoo-duhn-it ]
/ huˈdʌn ɪt /

noun Informal.

a narrative dealing with a murder or a series of murders and the detection of the criminal; detective story.
Also especially British, who·dun·nit.

Origin of whodunit

1925–30; jocular formation from question Who done it?, for standard English Who did it?

British Dictionary definitions for whodunnit

whodunnit

whodunit

/ (huːˈdʌnɪt) /

noun

informal a novel, play, etc, concerned with a crime, usually murder