Questions & Answers about Кіт чухається.
-ся is the reflexive marker. It often corresponds to English oneself / itself.
So:
- чухати = to scratch something
- чухатися = to scratch oneself / itself
In Кіт чухається, the cat is doing the action to itself, not to some other object.
The dictionary form is чухатися.
чухається is the 3rd person singular present form, used with він / вона / воно and with singular nouns like кіт.
A few present-tense forms are:
- я чухаюся = I scratch myself / I am scratching myself
- ти чухаєшся = you scratch yourself
- він/вона чухається = he/she scratches himself/herself
So кіт чухається literally matches the cat scratches itself / is scratching itself.