(informal, figuratively) to conceal one's true feelings, to hide what one really thinks, not to reveal one's true convictions or allegiances

(figuratively) to nourish a viper in one's bosom

(figuratively) to nourish a viper in one's bosom

(figuratively) to shoot oneself in the foot

(figuratively) to put on the ritz, put on the dog, put on a great spread, lay out a real spread, pull out all the stops, to get the good/best china out

(figuratively) to have more than one trick up one's sleeve, to have more than one string to one's bow

(vulgar) to be fucking blind, to not notice the obvious

(intransitive, figuratively, informal) not to go in for half-measures, not to half-ass it; not to embarrass oneself with manners

(informal) for there to be trouble brewing, for there to be tension in the air

(informal) to look each other straight in the eye, to stare each other down, to glare at one another