"Calor" means heat; it's a noun, not an adjective. Just because sometimes the most natural English translation involves the word "hot," that doesn't mean that's what calor means. A literal translation of "hace calor" would be "it makes heat."
But what a word "means" is itself influenced by the language you're thinking in right? This quiz isn't asking for the word to describe a concept superseding language, it's asking for the word that means "hot"… which is a word in English, not a universally understood wordless idea. I strongly feel that any reasonable translation of any of the common English meanings of the world "hot" should be allowed, because that's essentially what the question is asking for.
And it’s King Charles now