to act on a sense organ or organism to produce a response; to cause a physiological or biological reaction

to irritate; to sting; to affect the sense organs in a way that causes discomfort, such as strong light or chemical irritants

stimulus; stimulation; a source of provocation or physical/mental excitement

to upset; to shock; to cause a strong emotional or mental impact, such as a setback or frustration

exciting; thrilling; provocative; used as a describing word for things that provide intense sensory or mental excitement

to provide incentive or promote a positive change in a situation, such as the economy or work enthusiasm