Learn English – term for words which are insults but not vulgar

Sometimes, when I explain a new word to a friend who doesn't speak English well, I know that the word has to be used carefully, because it is not appropriate in all contexts, or can be offensive if used in the wrong way (or used at all). And I try to convey to the friend a feeling of what is dangerous about a word, so they will not use it inappropriately. Interestingly, languages (and cultures) have different reasons why a word can be dangerous, but today I am thinking of words which are insulting. For insults, I know broadly three sub-categories:

1. Words which are OK in their primary meaning, but insulting when applied to a human.

   That cow from Accounting lost my receipt.

2. Words which are specifically meant as an insult, but are not dirty. A conservative grandmother won't let her grandchild apply the word to another person, but won't be appalled at the child knowing the word.

   That nitwit from Accounting lost my receipt.

3. Words which are not just insults, but also vulgar, and considered taboo in some situations.

   That bitch from accounting lost my receipt.

What I am looking for is for a term for the second category above. And it should not be just an umbrella term which also includes one or both of the two other categories, but one which makes it clear which one is meant. Just like

"Bitch" is a curse word.

makes it clear that "bitch" is not in category 1 or 2, I am asking if there is a term which could be used in the sentence

"Nitwit" is a _____ word.

would not only make it clear that nitwit is an insult, but also that it is not in category 1 or 3.

I am aware that there are many descriptive ways to express that, for example "non-curse insult", but I have a nagging feeling that I have encountered a single-word term that is specific to that exact category, and have forgotten it. After talking to some people, I am starting to doubt if this term exists, but if it does, I hope the community here will find it.

I am not sure that the term is used in a noun phrase with "word", so maybe the example should simply be "Nitwit is a ____".