nouna syntactic construction, often considered ungrammatical in standard Modern English, in which two negatives are used where one is needed, as in I wouldn't never have believed it
▶ USAGE There are two contexts where double negatives are used. An adjective with negativeforce is often used with a negative in order to express a nuance of meaning somewherebetween the positive and the negative: he was a not infrequent visitor; it is a not uncommon sight. Two negatives are also found together where they reinforce each other rather thanconflict: he never went back, not even to collect his belongings. These two uses of what is technically a double negative are acceptable. A thirdcase, illustrated by I shouldn't wonder if it didn't rain today, has the force of a weak positive statement (I expect it to rain today) and is common in informal English