Okey-dokey
Okay. There are some late 20th century alternative meanings, limited to the USA, e.g. 'absurd or ridiculous' and 'to swindle of deceive'.

A friend in need is a friend indeed
It is sometimes suggested that this phrase means 'someone who needs your help becomes friendly in order to obtain it'. That isn't supported by the derivation (below). Most people understand it to mean, 'someone who helps you when you are in need is a true friend'.

Head over heels
Excited, and/or turning cartwheels to demonstrate one's excitement.

Saved by the bell
Saved by a last minute intervention.

Keep body and soul together
To survive. The phrase is most often used specifically to refer to earning sufficient money to keep oneself alive.

Over the moon
Very happy or delighted.

Out of sight, out of mind
The idea that something is easily forgotten or dismissed as unimportant if it is not in our direct view.
[find out more phrases meaning and origin from here]