懐メロ: an old hit song, an oldie, a golden oldie

硬口蓋音: palatal consonant

implant (anything surgically implanted in the body), usually dental implants

Des Moines (the capital city of Iowa) / Des Moines (a city in Washington) / Des Moines (a village in New Mexico) / Des Moines (a river in the United States)

polyyne

(computing) plug-in

(baseball) high and inside; a pitch thrown near the top the strike zone, relatively close to the batter / short for インターハイ (“inter-high school sports tournament”).

(slang, ACG) simple-minded heroine

incel

to go to bed (with someone)