Something that undulates has gentle curves or slopes, or moves gently and slowly up and down or from side to side in an attractive manner.
例句
As we travel south, the countryside begins to undulate as the rolling hills sweep down to the riverbanks...我們一路南行，鄉(xiāng)間開(kāi)始變得起伏不平，綿延的山巒一直延伸到河岸。His body slowly undulated in time to the music.他的身體隨著音樂(lè)的節(jié)拍慢慢擺動(dòng)。