source: The "Help Identifying This Anime/Character" Thread (v4) (660 - ) - Forums - MyAnimeList.net

adjective (nastier, nastiest)

1. highly unpleasant, especially to the senses; physically nauseating:

｟話｠ 不快な, いやな(unpleasant); ひどく不潔な

e.g. plastic bags burn with a nasty, acrid smell.

(of the weather) unpleasantly cold or wet:

荒れた, 危険な〈天候･海など〉

e.g. a cold, nasty day.

repugnant to the mind; morally bad:

〖通例名詞の前で〗やっかいな, 扱いにくい〈問題･状況〉; 深い〈驚きなど〉; ぞっとするような〈経験〉; いやな, 好まれざる〈習性など〉

e.g. her stories are very nasty, full of murder and violence.

2. (of a person or animal) behaving in an unpleasant or spiteful way:

〈言動･人などが〉 【人に対して】意地の悪い, 悪意のある(malicious) «to»

e.g. Harry was a nasty, foul-mouthed old devil

e.g. when she confronted him, he turned nasty.

annoying or unwelcome:

e.g. life has a nasty habit of repeating itself.

3. physically or mentally damaging or harmful:

｟くだけて｠ 〈病気･けがなどが〉ひどい, 重い

e.g. a nasty, vicious-looking hatchet.

noun (plural nasties) (often nasties) informal

an unpleasant or harmful person or thing:

〖-ties〗いや, 不快, 有害な人, 物

e.g. bacteria and other nasties.

a horror video or movie.

ホラー映画

nastily |ˈnastəlē| adverb

late Middle English: of unknown origin.