Your name is mud.
You are in trouble, will be punished, are going to suffer, etc. (This expression is related to Dr. Mudd, a physician who was convicted of helping the assassin of Abraham Lincoln. As punishment, Mudd was sent to a prison where he saved many lives during an epidemic. Hero or bad guy? The controversy continues. From what I've read, Mudd had met the killer prior to the assassination and knew exactly who he was. Bad guy!)
If you don't get to the office on time this morning, you're name is going to be mud. You've been late twice this week.
His name will be mud if boss finds out John has been dating his daughter.
To be back to square one.
To begin again, to start over
I was saving my money to buy a car, but I lost it all in a poker game. Now it's back to square one. I'll have to start saving money again.
The detectives questioned all the witnesses without discovering any new clues. They are going to begin the investigation all over again. Tomorrow it's back to square one.
Excuse my French
Excuse me for using vulgar language
(Note that the speaker is implying that he just said something in French. Not true. He is merely apologizing for using coarse language.)
Damn it! Excuse my French, but I just cut my finger on a piece of broken glass. Man, it smarts! (see below)
To hurt (humorous)
I saw you fall off the bicycle. It had to smart!
Did you see the soccer player break his leg last night? I bet it smarted!
Shit, mess, lies, trouble, etc.
("Shit" is definitely a vulgar word and should be avoided. "Crap" is also vulgar but it's more accepted than "shit". Neither word should be used in formal situations.)
Oh, crap! Excuse my French (see above), but I just realized that I left my briefcase at home.
I have a lot of crap in my car. It's a real mess!
He got into some crap with the local police.