Simple past tense and past participle of bolster.(verb)
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Use "bolstered" in a sentence
"The win bolstered Louisville's hope for a Jan. 2 bowl bid."
"The fact that Menendez did have my name bolstered my suspicions that my problems didn't lie with Zerak and the campaign."
"But behind the Italian fashion house's prosperity is an extraordinary story, of a family beset by controversy and war, and a fashion label bolstered by the earliest kind of celebrity endorsement."