on a mission UK /ɒn‿ə ˈmɪʃn̩/US /ɑn‿ə ˈmɪʃən/ prepositional phrase2 •Actively and determinedly engaged on a task.So she walked and as the night begun^([sic]) to engulf the countryside Emily still did not tire, she was on a mission; a mission to save her friend, her sister. — 2014 •(slang) Looking for drugs; on a drug run.I'm slipping on my khaki suit (Which one?) / The blue one, gun by my side as I mob to the beach / On a mission and I'm fishing for my DJ Warren G — 1993
