classify UK /ˈklæs.ɪ.faɪ/US /ˈklæs.əˌfaɪ/ verb3 •to identify by or divide into classes; to categorizeShould we classify "make up" as an idiom or as a phrasal verb? •to declare something a secret, especially a government secretThey decided to classify that information. •To make classy formsclassified · classifying · classifies