to strengthen with some added piece, support, or material

to reinforce a wall.

to strengthen (a military force) with additional personnel, ships, or aircraft

to reinforce a garrison.

to strengthen; make more forcible or effective

to reinforce efforts.

to augment; increase

to reinforce a supply.

Psychology . to strengthen the probability of (a response to a given stimulus) by giving or withholding a reward.

something that reinforces.

a metal band on the rear part of the bore of a gun, where the explosion occurs.

verb

subtract , take away , undermine , weaken

verb

add fuel to fire , add to , back up , beef up * , bolster , boost , build up , buttress , carry , emphasize , energize , enlarge , fortify , harden , heat up , hype , increase , lend a hand , multiply , pick up , pillar , prop , prop up , punch up , shore up , soup up , stand up for , stiffen , stress , stroke , supplement , support , sustain , toughen , underline , strengthen , augment , back , brace , shore