From Longman Dictionary of Contemporary Englishtwitterjackingtwit‧ter‧jack‧ing /ˈtwɪtəˌdʒækɪŋ $ -tər-/ noun [uncountable]the activity of sending out a Twitter message using someone else's name, usually a well-known person's —twitterjack verb [intransitive] —twitterjacker noun [countable]