A kind of fungus.
It depends on what you mean by 'four letter word'. Thea has four letters, so yes it is. It is not a swear word, so it's not that kind of 'four letter word'.
Hare
Fish
Mushrooms are a kind of fungus that people like to eat.
Type.
kiss kick kind knit
kind, eked, oaks, tank
kill, kind, kiss, Kris
Kind, kill, keep, kink, kook
kind, king, kohl, kilt, kids,
Loudmouth
A four letter word starting with the letter a is able.