A kind of guided missile. / (military aviation) A guided air-dropped bomb. / (video games) A weapon that damages or kills all enemies within a large area.

(simile) Very intelligent.

(Canada, US, informal) Very intelligent.

(informal) Alternative form of smart arse

(informal) having the irritating qualities of a smart arse, with a know-it-all attitude.

plural of smart-arse

plural of smart bomb

A mobile device worn on the wrist, often with a display that can be used to control a smartphone or to keep track of information such as fitness levels.

plural of smart phone

Alternative form of smartphone