nevermind (n.)

Middle English never, from Old English næfre "not ever, at no time," a compound of ne "not, no" (from PIE root *ne- "not") + æfre "ever" (see ever). Early used as an emphatic form of not (as still in never mind). Old English, unlike its modern descendant, had the useful custom of attaching ne to words to create their negatives, as in nabban for na habban "not to have."

Italian giammai, French jamais, Spanish jamas are from Latin iam "already" + magis "more;" thus literally "at any time, ever," originally with a negative, but this has been so thoroughly absorbed in sense as to be formally omitted.

Phrase never say die "don't despair" is from 1818. Never Never Land is first attested in Australia as a name for the uninhabited northern part of Queensland (1884), perhaps so called because anyone who had gone there once never wished to return. Meaning "imaginary, illusory or utopian place" is attested by 1900 in American English. J.M. Barrie's use of the full form for the island home of the Lost Boys is by 1905.

mid-14c., "to remember, call to mind, take care to remember," also "to remind oneself," from mind (n.). The Old English verb was myngian, myndgian, from West Germanic *munigon "to remind." Meaning "perceive, notice" is from late 15c.; that of "to give heed to, pay attention to" is from 1550s; that of "be careful about" is from 1737. Sense of "object to, dislike" is from c. 1600. Meaning "to take care of, look after" is from 1690s. Related: Minded; minding.

Negative use "(not) to care for, to trouble oneself with" is attested from c. 1600; never mind "don't let it trouble you" is by 1778; the meiotic expression don't mind if I do is attested from 1847.