An onomatopoeic adverb meaning to toss or fling something casually or carelessly.
彼はゴミをポイポイ捨てるので、周りの人に注意された。
He casually throws away trash, so people around him warned him.
子どもがぬいぐるみをポイポイ放り投げた。
The child tossed the stuffed toy carelessly.
読み終わったチラシをポイポイ机の上に置いた。
He put the flyer he had finished reading carelessly on the desk.