impulse
/ˈɪmpʌls/
In a psychological context, it describes a sudden, visceral drive that bypasses rational deliberation. It carries a sense of spontaneity, often bordering on recklessness or lack of self-control. Unlike a 'whim', which is light and playful, an impulse feels more like an internal pressure demanding immediate release. In technical and biological contexts, the word shifts from emotional to mechanical. It represents a discrete burst of energy or information—a 'spike' that triggers a reaction. The feeling here is one of transmission and activation rather than desire. In physics, it is a precise measurement of force applied over time, focusing on the transition of motion. This usage is strictly clinical and devoid of the emotional volatility found in the psychological definition.
Countable when referring to a sudden whim ('an impulse to scream') or a distinct electrical signal ('a nerve impulse'). Uncountable when discussing the physics concept of momentum change over time.
💬Casual Conversation
Just bought a 70-inch TV on an impulse. My bad.
You're actually out of your mind. You can't even pay rent.
Meanings
Etymology
Derived from the Latin word impulsus, which is the past participle of impellere, meaning to push forward or drive. This is a combination of the prefix in- meaning into or upon and pellere meaning to drive. The term entered English in the 17th century, initially referring to a physical push or a driving force before evolving to describe psychological urges and electrical signals.