Does the word “semantics” make sense in this context

Question

I’d like to know if “semantics” is the right word to use here:

He didn’t care about grammar or semantics. If something made sense to him in his head, he unabashedly voiced it.

If not, what word do I replace it with?

Answer 1

Interestingly your question is about semantics. You have two problems, or maybe three, which you need to make sure don't mess up the semantics of your sentence.

1. What exactly is meant by "semantics"?

Google/Lexico's definition couldn't be more clear:

the branch of linguistics and logic concerned with meaning

That is exactly what semantics is. It is about meaning. So when you talk about the semantics of a passage, you are talking about its meaning. If you are dealing with semantics in general you work in a field that looks exclusively at textual meaning and production of meaning.

2. Now that we are clear on the meaning of "semantics", is it subsumed under "grammar". If it is then semantics is redundant and unnecessary.

As per this orthodox answer, "grammar" as a linguistic concept refers to syntax and morphology.

Grammar is syntax and morphology.

Grammar is not semantics, pragmatics, phonology, orthography, or the lexicon.

So you are in the clear with that sentence: it makes sense.

3. But wait, we are not done yet. The sentence makes sense doesn't mean it means what you intend it to mean. You are asking if you should use semantics or another word, but you are the one writing that line. It's up to you. What do you mean to say with that line? If you indeed intend to say "He didn't care about the meaning." then that line is a go.