From Longman Dictionary of Contemporary English(I’ll be/I’m) damned if ...(I’ll be/I’m) damned if ...spoken not polite used to make a negative statement in a strong way‘Where’s Wally?’ ‘Damned if I know.’ (=I don’t know)I’ll be damned if I can find my keys (=I can’t find them).I’ll be damned if I let him in the house (=I won’t let him in). → damn
