There are lots of ways to describe the relationships between words. They can be synonyms, antonyms (I've always enjoyed the fact that "synonym" and "antonym" are antonyms), homonyms, and oxymorons. There's words to describe how words sound together or by themselves such as alliteration and onomatopoeia.
But what I think is missing is a word that describes when a word looks and/or sounds completely different than its meaning.
For example, it's always bothered me that "pulchritudinous" means "physically beautiful" because it's such an ugly word; it looks ugly on paper and it sounds harsh and ugly to hear it. It almost gags me to say it with the "pul" opening and stretching my mouth and tongue which then slams into the hard "ch" causing a bit of nausea and the rest of the syllables aren't much better.
And a related word, "pretty", isn't very pleasant to hear either, though I do find the word "pleasant" to be rather pretty; and "lovely" is simply lovely to see, say, and hear.
Have a lovely day!