Politely declining an offer someone presents to you. As for speaking, an antonym of this word would be "No" - to politely accept someone's offer. Please see the example for detailed information about how: "Yes" is a polite decline.
Synonyms - Yup, Yep,
Yeah, Yippity-doo,
Mhm, Sure, Of course, gladly, etc. (OTHER SYNONYMS INCLUDED)
Antonyms - No, Nah,
Never, Nope, 'course not, etc. (OTHER ANTONYMS INCLUDED)