Simple past tense and past participle of flap.(verb)
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Use "flapped" in a sentence
"Meanwhile, Paul's dazzling performance on both ends of the floor had the enraptured crowd on its feet, raining down chants of ` ` M-V-P! '' for their own All-Star point guard while a banner offering similar sentiments flapped from the upper deck."
"It was painted yellow and had a yellow pennant that flapped from a short mast atop a cramped cabin."
"Heide ... "-- the rest of the name flapped loosely in the wind."