Beg off is an informal phrasal verb that means to decline or refuse an invitation or request. Antonyms of beg off include accept, agree, comply, and accede. If someone is unable to beg off from an invitation, they must accept it. On the other hand, if someone is willing to accept an invitation, they are effectively avoiding the need to beg off. To comply with someone is to agree with their request and follow through with it. When someone accedes to a request, they are agreeing to it, even if they don't entirely support it. Ultimately, choosing the right antonym of beg off depends on the context in which the word is being used.