Simple past tense and past participle of conk.(verb)
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Use "conked" in a sentence
"One engine "conked" and he was forced to turn back."
"A Manhattan woman has sued a lower East Side restaurant, claiming she was conked in the head by a moosehead that fell off a wall."
"All the palms in town were kept free of coconuts so that tourists wouldn't get conked on the head by falling coconuts and parked cars wouldn't get dented."