Also, put one's cards on the table. Be open and honest, reveal one's position or intentions, as in John laid his cards on the table and told her how much they could afford. This expression alludes to showing the hand one holds. [c. 1900] Also see show one's hand.
The American Heritage® Idioms Dictionary Copyright © 2002, 2001, 1995 by Houghton Mifflin Harcourt Publishing Company. Published by Houghton Mifflin Harcourt Publishing Company.