stress
1.Physiology. a specific response by the body to a
stimulus, as fear or pain, that disturbs or interferes with the normal
physiological equilibrium of an organism.
2.physical, mental, or emotional
strain or tension: Worry over his job and his wife's health put him under a
great stress.
3.a situation, occurrence, or factor causing this: The stress
of being trapped in the elevator gave him a pounding headache.