Not really. You could block (almost all) code execution with something like:
function sleep(ms:int):void {
var init:int = getTimer();
while(true) {
if(getTimer() - init >= ms) {
break;
}
}
}
trace("hello");
trace(getTimer());
sleep(5000);
trace("bye");
trace(getTimer());
But I don't see how could this be useful in flash. And, at the same time, anything like the above code is a very bad idea as the player will freeze and become unresponsive (and could also give a script timeout if you exceed the timeout limit, which is 15 by default).
If you merely want to delay the execution of a piece of code, you can use a Timer object or the setTimeout function. This will be non-blocking, though, so you'll have to use some kind of flag like TandemAdam suggested. It'll be brittle, at best.
Maybe there's a better approach for your problem, but it's not clear what are you trying to accomplish in your question.