Antonyms are words with opposite meanings, and language is littered with them. For reference, here are a few examples:
Hot, cold
Fast, slow
Big, small
Short, tall
As you can see, many antonyms are modifiers (adjectives and adverbs), but that isn’t always the case. You can have noun antonyms (male, female), verb antonyms (go, stop), pronoun antonyms (he, she), preposition antonyms (to, from), and so forth. In fact, I would go as far as to say that most words have an antonym of some kind.
