Simple past tense and past participle of counter.(verb)
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Use "countered" in a sentence
"Though McCain countered by resorting to bare-knuckle tactics in the subsequent Michigan primary, and won it by seven percentage points, the Senator's heart wasn't in such methods."
"McCain countered, It's got to be one or the other."
"“Passive voice can be used to deflect responsibility; Biden used active voice when referring to Cheney and Bush; Palin countered with passive deflections.”"