Where does “anti-nightcore” come from?

anti-nightcore (English) comes from English nightcore, from English Core, from English -core, from English hardcore, from English hard, from Old French hardi, from Old French hardir, from Frankish hardijan — to travel, tour.

Ancestry of “anti-nightcore”, step by step

anti-nightcore traces back through two separate lines of ancestry.

via English nightcore

StepLanguageWordMeaning
1EnglishnightcoreA plunderphonic style of music based on taking an...
2EnglishCoreThe birth name of Persephone/Proserpina, the queen of the Underworld/Hades, and goddess of the seasons and of vegetation. She is the daughter of Zeus and Demeter, and the wife of Hades
3English-coreApplied to various genres of music and...
4EnglishhardcoreHaving an extreme dedication to a certain...
5EnglishhardHaving a severe property; presenting difficulty;...
6Old Frenchhardihardy; tough; durable
7Old Frenchhardirto harden
8Frankishhardijanto harden, to make hard
9Proto-Germanichardijanąto make hard, strong; to harden
10Proto-Germanicharduzhard; brave
11Proto-Indo-Europeankert-times; to weave, twist together; time
12Proto-Turkic*keŕ-to travel, tour

via English anti

StepLanguageWordMeaning
1EnglishantiOpposed to something; That has a torsion angle...
2Englishanti-Against, hostile to; Contrasting with the norm;...
3Ancient Greekἀντι-anti-, against; like, reminiscent of
4Ancient Greekᾰ̓ντῐ́opposite
Every word from Proto-Turkic *keŕ-Every word from Proto-Indo-European kert-Every word from Proto-Germanic harduz