Mad as a hatter Mad as a march hare Magical realism Main chance Make a bee-line for Make a clean breast of it Make a virtue of necessity Make haste Make him an offer he can't refuse Make my day Make no bones about Make your hair stand on end Mal de mer Man after my own heart - A Man does not live by bread alone Man's inhumanity to man Many are called but few are chosen Many happy returns Many a true word is spoken in jest Marital aid Market forces Marry in haste, repent at leisure May you live in interesting times McCoy - The real Mea culpa Meat and drink Meat and two veg. Meet your Waterloo Men in suits Mend fences Ménage à trois Men's evil manners live in brass; their virtues we write in water Merry Christmas Mexican wave Mickey Finn Middle of the road Might and main (The pen is) mightier than the sword Mighty oaks from little acorns grow Milk of human kindness Minced oaths Mind your p's and q's Ministering angel shall my sister be - A Misery acquaints a man with strange bedfellows Misquotations Moaning Minnie Mondegreens Montezuma's Revenge Monty - The full Moot point Morbid obesity More fool you More honoured in the breach than in the observance Morning person Mother country Motley crew Mouth-watering Moveable feast Moving finger writes - The Moving the goalposts Much Ado about Nothing Much of a muchness Mud - your name is Multitude of sins Mumbo jumbo Mum's the word Murphy's Law Music has charms to soothe the savage breast Mutt's nuts - The Mutt and Jeff My bad My better half My cup runneth over My giddy aunt My husband and I My mind's eye My old china My old Dutch My salad days