Naught means nothing: not a thing, zero. Young people almost never say this word in ordinary talk. They say nothing, or zero. You meet naught in books, old poems, and a few set phrases that are still alive. The one you will see most is all for naught: you did the work, but you got nothing back. Come to naught means a plan failed and ended as nothing. Though actually, British English often writes this as nought, especially for the number 0 (nought point five for 0.5). Naught and nought are the same old word with two spellings, and many writers treat them as one. The word is not rude. It just sounds like a storybook, not like a phone message.