also tip one's mitt : to declare one's intentions or reveal one's opinions or resources <the Justice Department wouldn't tip its hand by saying what its next move ⋯ would be ― Newsweek >
TIP ONE'S HAND
Meaning of TIP ONE'S HAND in English
Merriam Webster Collegiate English Dictionary. Merriam Webster - Энциклопедический словарь английского языка. 2012