反掌

lit. to turn over one's palm / fig. everything is going very well.

contrary / in reverse / inside out or upside down / to reverse / to return / to oppose / opposite / against / anti- / to rebel / to use analogy / instead / abbr. for 反切[fan3 qie4] phonetic system

palm of the hand / sole of the foot / paw / horseshoe / to slap / to hold in one's hand / to wield

easy as a hand's turn (idiom); very easy / no effort at all

see 易如反掌[yi4 ru2 fan3 zhang3]