HSK10+
pífúhàndàshù
fig. to overrate one's own strength
蚍蜉撼大树 (蚍蜉撼大樹)
lit. an ant trying to shake a big tree (idiom); fig. to overrate one's own strength; also written 蚍蜉撼樹|蚍蜉撼树[pífúhànshù]
CC-CEDICT