BEST and WORST are synonyms when used as verbs:

he bested his opponent, he worsted his opponent

But they’re antonyms when used as adjectives, adverbs, or nouns:

the best player, the worst player

it best suits his skills, it worst suits his skills

I am the best, I am the worst

William James wrote, “Language is the most imperfect and expensive means yet discovered for communicating thought.”