reinforce (v.)

• accelerate
• affirm
• aggravate
• attest
• augment
• authenticate
• back
• bear
• bolster
• brace
• buttress
• carry
• certify
• circumstantiate
• complicate
• concentrate
• condense
• confirm
• consolidate
• corroborate
• cradle
• cushion
• deepen
• document
• double
• energize
• enhance
• enlarge
• exacerbate
• exaggerate
• finance
• fortify
• fund
• gird
• harden
• heighten
• hold
• increase
• intensify
• invigorate
• keep
• magnify
• maintain
• multiply
• nerve
• pillow
• probate
• prop
• prove
• ramify
• ratify
• recruit
• redouble
• refresh
• reinvigorate
• restrengthen
• rigidify
• sharpen
• shore
• shoulder
• stay
• steel
• stiffen
• strengthen
• subsidize
• substantiate
• subvention
• supplement
• support
• sustain
• temper
• tense
• tighten
• toughen
• triple
• undergird
• underlie
• underpin
• uphold
• validate
• verify
• warrant
• whet