露出马脚

lù chū mǎ jiǎo

to reveal the cloven foot (idiom); to unmask one's true nature

to give the game away

dew

chū

variant of 出[chu1] (classifier for plays or chapters of classical novels)

abbr. for Malaysia 馬來西亞|马来西亚[Ma3 lai2 xi1 ya4]

jiǎo

foot