extemporaneous act

Definitions

An action performed without prior planning, preparation, or rehearsal.

A spontaneous deed carried out on the spur of the moment.

Examples

The comedian's hilarious monologue was an extemporaneous act that left the entire audience in stitches.

Her decision to donate the prize money to charity was an extemporaneous act of kindness that surprised everyone in the room.

Synonyms

impromptu performance spontaneous action unrehearsed deed improvised maneuver off-the-cuff behavior

Antonyms

premeditated act rehearsed performance planned maneuver scripted action deliberate deed