alter, change, modify - cause to change; make different; cause a transformation; "The advent of the automobile may have altered the growth pattern of the city"; "The discussion has changed my thinking about the issue"

vitalise, vitalize - make more lively or vigorous; "The treatment at the spa vitalized the old man"

ruggedise, ruggedize - produce in a version desigend to withstand rough usage; "Detroit ruggedized the family car"

substantiate - solidify, firm, or strengthen; "The president's trip will substantiate good relations with the former enemy country"

restrengthen - make strong again

brace up, undergird - make secure underneath; "undergird the ship"

confirm - make more firm; "Confirm thy soul in self-control!"

reenforce, reinforce - make stronger; "he reinforced the concrete"

buttress - make stronger or defensible; "buttress your thesis"

stabilise, stabilize, steady, brace - support or hold steady and make steadfast, with or as if with a brace; "brace your elbows while working on the potter's wheel"

batten - secure with battens; "batten down a ship's hatches"

batten, batten down, secure - furnish with battens; "batten ships"

change - undergo a change; become different in essence; losing one's or its original nature; "She changed completely as she grew older"; "The weather changed last night"

consolidate - make firm or secure; strengthen; "consolidate one's gains"; "consolidate one's hold on first place"

proof - make resistant to water, sound, errors, etc.; "proof the materials against shrinking in the dryer"

back - strengthen by providing with a back or backing

sandbag - protect or strengthen with sandbags; stop up; "The residents sandbagged the beach front"

toughen - make tough or tougher; "This experience will toughen her"

exercise, work out - do physical exercise; "She works out in the gym every day"