(on the Twitter website) a hostile or otherwise negative post that is addressed to or about a particular person but does not mention the person’s username or does not name the person at all.
verb (used with or without object)
to post such a message or tweet about (someone) on Twitter: I wish she’d stop subtweeting and talk to me in person.
Origin of subtweet
Dictionary.com Unabridged Based on the Random House Unabridged Dictionary, © Random House, Inc. 2019