nevermind

noun Older Use.

1. attention; heed; notice (usually used in negative constructions): Pay him no nevermind.
2. business; affair; responsibility (usually used in negative constructions): It’s no nevermind of yours.

n.also never-mind “difference, matter for attention,” 1935, American English, from verbal expression never mind “forget it,” originally never mind it attested by 1795; see never + mind (v.).