Larger than life — exceedingly imposing, impressive, or memorable
Take a fancy to — take a shine to, become fond of
Rare as hen’s teeth — exceptionally rare or nonexistent [Mid-1800s]
Snap to it! — hurry up!
Knee-high to a grasshopper — very small or young [USA 1814]
That’ll put hair on your chest — make you stronger
Give the gears — Harass, pester or tease (Canadian)
Knock the stuffing out of — beat up someone physically or mentally
A bridge too far — a goal too ambitious (WWII, Sept/44 — Operation Market Garden)
Hotter than the hinges of hell — VERY hot
Music to my ears — pleasing news (late 16th century)
Horn in — intrude or interrupt (American cowboy slang, 1880)
Lock horns — argue (based on two fighting animals such as deer)
Rainforest Writer 