very nasty remark fired at someone, usually in an exchange of
insults; verbal response to a cutting put down in an argument, but not always seriously; the name of the nastiest insult thrown out as the last word in argument; sarcastic response to a nasty remark

A portmanteau of carpe diem, a Latin phrase that means “Seize the Day!” and DM, which stands for Direct Messages. This word means seizing the day via DMs.