1. the use of physical or mental energy to do something; exertion.
2. A difficult exertion of the strength or will: it was an effort to get up.
3. A usually earnest attempt: make an effort to arrive promptly.
4. something done or produced through exertion; an achievement: a play that was his finest effort.
5. physics force applied against inertia.

1. the work involved in performing an activity; exertion.
2. an endeavour.
3. to make an effort.
4. to stimulate.

1. an exertion of strength or power, whether physical or mental, in performing an act or aiming at an object; more or less strenuous endeavor; struggle directed to the accomplishment of an object.
2. A force acting on a body in the direction of its motion.
3. to stimulate.

1. to strengthen; reinforce.
2. voluntary exertion; a putting forth of the will, consciously directed toward the performance of any action, external or internal, and usually prepared by a psychological act of “gathering the strength” or coördination of the powers.
3. the result of exertion; something done by voluntary exertion; specifically, a literary, oratorical, or artistic work.
4. in mech., a force upon a body due to a definite cause.

1. earnest and conscientious activity intended to do or accomplish something
2. use of physical or mental energy; hard work
3. a notable achievement
4. a series of actions advancing a principle or tending toward a particular end