jagged, serrated / uneven, chequered, inconsistent

(figuratively) to aim high, to set one's sights high, to be ruthlessly ambitious, to be fiercely competitive

(figuratively) to smile from ear to ear, to smile all over one's face, to grin like a Cheshire cat

(equestrianism) to champ at the bit / (figuratively) to get the bit between one's teeth

(idiomatic) to remain silent

sabre-toothed tiger

(simile, informal) to lie through one's teeth, to lie brazenly, shamelessly

(idiomatic, sarcastic, figurative, adynaton, hyperbolic) when Hell freezes over; when pigs fly (never)

(figuratively, derogatory) to be unscrupulously ambitious

(figuratively, informal) to feel like one is going to throw up (usually because one has eaten too much and is stuffed to the gills)