minus

Minus is the neuter comparative of parvus, "small", and it works both as an adverb, "less", and as a noun, "a smaller amount". The full ladder is parvus, minor, minimus for the adjective and parum, minus, minime for the adverb, and it is worth learning as a block, because minor and minimus turn up far more often than parvus itself.

Comparison uses quam, minus quam, or the plain ablative of comparison with no quam at all.

Two idioms repay memorising. Nihilo minus, often written as one word nihilominus, is "none the less". And after si, nisi and quo the word is a courteous understatement for a flat no: si minus means "if not", si minus potes means "if you cannot". The superlative minime does the same job on its own and is the standard Latin word for "no" in answer to a question.