1o_ First (as 'I'), second (as 'you' ) and third (as 'he/she' ) people in singular present of the subjunctive mode, and second (as 'you' ) and third (as 'he/she' ) singular imperative people for the verb gafar. See verbs/gaffe . 2o_ It's something or someone who brings "bad luck". The origin is in a type of leprosy known as 'gafedad', because people were fleeing the leper so that they did not get the disease.
