card up one's sleeve

card up one's sleeve  {n. phr.},  {informal}
Another help, plan, or argument kept back and produced if needed; another way to do something.
John knew his mother would lend him money if necessary, but he kept that card up his sleeve.
Bill always has a card up his sleeve, so when his first plan failed he tried another.
Compare: ACE IN THE HOLE (2).
Categories: sleeve {informal} {n. phr.}