Texting abbreviation of the phrase, "Might As Well Be."
Ken sends a text, calling Barry down the pub, Barry text's back, saying he can't, he's been given orders by her indoors. 'You act like an old married couple you two', text's Ken, disgusted and forlorn. Barry, who has to be quick, Jude giving him the evil eye replies, 'mawb!'
by Michael Samuel May 20, 2008