More than pleased to help you Jackie !
The M word is spelled with only one R. "Merde".
Same kind of usage than in English, by the way. "Oh, shit!" when something goes wrong would be "Ah, merde!" in french. A "shitty day" would be "une journée merdique".
But also, when you want to wish good luck to someone and you say "brake a leg!" in English, well, you can say "merde!" in french.
Thanks for your answer and if you hear of some equivalent of AWAD in french, let me know !
Patrice-Guy