banjax /ˈbæn.d͡ʒæks/noun 1verb 1forms 3 noun1 •(Ireland, informal) A mess or undesirable situation made as a result of incompetence.I'm tellin' you the scholar, Bentham, made a banjax o' th' Will. — 1922 verb1 •(UK, slang) To ruin or destroy.I hoofed his backside till he went down all of a heap. That banjaxed his little game. You should have heard his hullabulloo. — 1922 formsbanjaxed · banjaxing · banjaxes