I could eat a horse
very hungry; starving
once in a blue moon
very rarely; infrequent
judge a book by its cover
decide based on appearance, without knowing what's inside
butterflies in your stomach
nervous; anxious
see eye to eye
agree fully or have a similar attitude
cost an arm and a leg
expensive; very costly
let the cat out of the bag
tell a secret; ruin a surprise
a tough cookie
physically or emotionally strong
lose your mind
go crazy
scream your lungs out
yell loudly
break a leg
do well; perform well for an actor
give him a hand
help out; offer assistance
under the weather
not feeling well; sick
broke your heart
very sad; devastated
hold your tongue
be quiet; don't speak
jump out of your skin
feel anxious; feel nervous
by the skin of your teeth
Barely; by a slim margin
don't beat around the bush
get to the point of what you want to say
stretch your legs
get up, take a walk
crack me up
hilarious; very funny
it's a piece of cake
Something is easy or simple