Synonyms for Buttress:

n.

get behind, endorse, promote, agree with, speak up for, ally, align, sympathize. joist, frame, gantry, rafter, shore, stanchion, scaffold, foundation, stay, framework. artifact (noun)
buttressing.
brace, support (noun)
shore, Underpinning, stanchion, prop, stay.
buttress (noun)
buttressing.
prop up (noun)
sustain.
support (noun)
Underpinning, backing, crutch.

v.

strengthen (verb)
fortify, vivify, temper, invigorate, empower, enliven, energize, reinforce, brace, beef up, strengthen, toughen, harden.
support (verb)
back, uphold, support, underpin, bolster, prop, hinge.
support, bolster (verb)
reinforce, uphold, sustain, beef up, brace, strengthen.

Other synonyms:

rafter, stanchion, joist, scaffold. framework, shore, foundation, gantry. frame. harden
toughen, harden.
Other relevant words:
framework, sustain, align, foundation, ally, joist, sympathize, stanchion, rafter, scaffold, endorse, stay, frame, buttressing, gantry, shore, promote.

Usage examples for buttress

  1. A thin buttress of rock ran down shoulder- high between the two men, and this Gordon had forgotten. – A Romance of Wastdale by A. E. W. (Alfred Edward Woodley) Mason
  2. But even a stage- setting as captivating as this might very well be justified if it had been employed to fill a gap in the action, and to buttress up the interest of an episode where the dramatist had allowed the appeal of his story to relax. – A Book About the Theater by Brander Matthews