How about everyone knowing what the word 'nocturnal' means, but they can't think of the word describing the opposite behaviour and resorting to using the word '

How about everyone knowing what the word 'nocturnal' means, but they can't think of the word describing the opposite behaviour and resorting to using the word 'normal'. nocturnal - Done, occurring, or active at night. [0] diurnal - 1. Of or during the day. 2. Daily; of each day. [1] crepuscular - Resembling or relating to twilight. [2] [0] https://en.oxforddictionaries.com/definition/nocturnal https://en.oxforddictionaries.com/definition/nocturnal [1] https://en.oxforddictionaries.com/definition/diurnal https://en.oxforddictionaries.com/definition/diurnal [2] https://en.oxforddictionaries.com/definition/crepuscular https://en.oxforddictionaries.com/definition/crepuscular