Mad as a cute sneak
Very mad. Go crazy and out of control

Made as a wet hen
Very mad, Very angry.

Made of money
Very rich

Make a better fist
Make something better

Make a clean breast of
Confess/ Admit the truth

Make a meal of something
Put extra effort to do something

Make a pig's ear
Mess up something

Make someone's blood boil
Make someone very angry

Make up one's mind
Make the decision

Make up with     
Recover close relationship

Man of means
Rich man

Made of straw
Weak person. A person who is not fight for anything

Man upstairs
Refer to god

Master of
Expert of

Meet a half way
Both parties accept to lose something to complete agreement

Memory like an elephant
Very good memory

Miss the bus / Miss the boat
Miss / lost some opportunities

Money for jam
Easy earned money.

Money to burn
Has a lot of money to spend with no worry.

Monkey business
Illigal business/ activity.

Month of Sunday
A very long month/ very long period of time.

Mountain to climb
Hard work to do ahead

My heart bleeds
Feel very sad or sympathy on something