The phrase "lost his shirt at the track" means that a man gambled so much on the races (horses, dogs, etc) that he spent all his money and had to resort to his clothing for this bets. Used as an idiom, this phrase means that someone has taken a, perhaps foolish, chance and lost.
"They will try to make you mad, but keep your shirt on while I make the deal." "The waitress told the impatient customer to keep his shirt on, and that he would be served when it was his turn."
It's not an idiom - to cope means to deal with, or to handle
It's not an idiom because you can figure it out by the context. It means they went bald.
It's a done deal - there is no chance of failure.
Meaning you snapped and got angry.
Yes, I lost my favorite shirt so I had to retrace my steps. is a pretty good sentence. You can improve it by doing this:I lost my favorite shirt, so I had to retrace my steps to find it.
To take an unhappy decision or result and deal with it resolutely
The origin of the idiom "lost your mind" can be traced to the early 1800s, where "mind" is used metaphorically to refer to one's sanity or mental faculties. The phrase implies that someone is irrational or behaving in a way that suggests they have lost their mental clarity.
The idiom, "You lost your marbles," means that you've gone crazy.
To say that there is no love lost between two people means that they dislike each other.
An idiom is a phrase that makes no sense unless you know the idiomatic definition. Can someone really lose his marbles? Yes, but does it make sense if someone says "He's lost his marbles" when someone says something crazy? No, so this can be either an idiom or an actual phrase. Someone could really misplace their marbles (toys), or they could be mentally unbalanced, in which case the idiom meaning would be used.