Are prat and git swear words or just slang?

Answer 1

People decide what words they will accept, and which they will not, as a group. There are parts of northern England where prat and git are generally acceptable, where you can even use them as terms of endearment to your friends. There are parts of the American south where they are very serious obscenities.

Neither Hull nor Tampa are 'correct': people choose which words are acceptable to them, and they are entitled to do so.

I would not be able to use the 'N' word on this site - because it is patroled by North Americans. But it is used as a term of affection in some late Nineteenth Century English novels, and is widely accepted in most of English-speaking central Africa.

Central Africa has a different term of racial abuse for person with black skin: so the N word doesn't carry much of a tabu out there. To use the local term of racial abuse is, naturally, a criminal offence.

Answer 2

"Prat" and "git" are considered more mild insults rather than swear words. They are generally seen as slang terms in British English to describe someone who is foolish or annoying.