Simple past tense and past participle of flex.(verb)
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Use "flexed" in a sentence
"Then, after the songs release the label flexed its muscles and said 'no' to radio stations playing it with no explanation given."
"Then, after the songs release the label flexed its muscles and said"
"But Kiffin flexed his muscles in recruiting — pulling in the No. 1 ranked class, according to Rivals. com — so there is enviable talent on hand as the Trojans try to reclaim the Pac-10 title after they went 5-4 in conference games, tied for fifth."