to play something by ear.
do something without a plan
To have a bun in the oven.
to be pregnant
It's my flesh and blood.
my relative
To get cold feet!
be nervous before a big event
In the blink of an eye.
very quickly
To stab someone in the back.
to betray someone
Turn a blind eye.
to ignore something wrong
To put your feet up.
to relax
To be head over heels.
completely in love
Over my dead body!
only when I die
To be thick in the head.
not very intelligent
Break a leg
good luck
To cost an arm and a leg
very expensive
To see eye to eye
to agree
You are pulling my leg!
You're joking
Keep your chin up!
don't despair
An old hand!
an experienced person
To have a skeleton in the closet/cupboard.
hidden secret