A person who cheats, is a cheat!

[GETTINGLIKEMYMOTHER]

NOT a cheater! I keep seeing it on MN, inc. just now. 🤬

Yes. I'll accept 'cheat' as a noun as well as a verb. In a few moments I might look in a dictionary.

I feel like there is a subtle difference. A "cheat" is someone who has cheated or who is cheating and a cheater is someone who is actively cheating and likely to continue. I'd say 'he's a cheater' with a bit more venom.

I did look up the difference and apparently, cheater is (etymologically) older than cheat to mean the same thing, but over time a subtle difference in meaning emerged as @SirenGirl says.

I've been googling. It's fascinating.