impulse
n. C / Un. a sudden, strong urge to do something without thinking about it first. You might feel this when you suddenly want to buy something you didn't plan to get.
n. a sudden, strong, and unreflective urge or desire to act. It typically implies a lack of premeditation or rational deliberation.
I had a sudden impulse to laugh during the quiet meeting.
She bought the expensive shoes on impulse, completely ignoring the strict budget she had set for the month.
The protagonist struggles constantly against his darker impulses, knowing that a single moment of unthinking anger could unravel years of careful diplomacy.
Borrowed from Middle French impulser, from Latin impulsus. For spelling, as in pulse, the -e (on -lse) is so the end is pronounced /ls/, rather than /lz/ as in pulls, and does not change the vowel (‘u’). Compare else, false, convulse.
Often followed by a 'to'-infinitive; frequently appears in the prepositional phrase 'on impulse' to denote spontaneous action.