相关单词近义词 underperform 表现不佳, disappoint 使失望, flounder 挣扎, drift 漂流, drop out 退出临近词under, undercool相似词under your breath idiom, under your feet idiom, under your own steam idiom, under-represented, underachiever, underactive, underage, underarm, 返回 underachieve