To keep up, impose or bring into effect something, not necessarily by force.
To give strength or force to; to affirm, to emphasize.
To strengthen (a castle, town etc.) with extra troops, fortifications etc.
To intensify, make stronger, add force to.
To exert oneself, to try hard.
To compel, oblige (someone or something); to force.
To make or gain by force; to force.
To put in motion or action by violence; to drive.
To give force to; to strengthen; to invigorate; to urge with energy.
To urge; to ply hard; to lay much stress upon.
To prove; to evince.