Impulse

(imf-puls) [impellere, to drive against]. I. A push or communicated force. 2. A sudden mental feeling that urges onward to an action. I., Cardiac, the beat of the heart felt in the fifth intercostal space to the left of the sternum. I., Morbid, a sudden, almost uncontrollable desire to do some unlawful or improper act. In- [L.]. I. A prefix signifying in or within. 2. A prefix signifying negation. 329