What is "stands up to"

Usage examples of "stands up to".

At last, bursting inexplicably into tears, she gives way, but when she stands up to sing, obviously at the end of her resources, weary, her arms not widespread as usual but hanging lifelessly down, so that one gets the impression that they are perhaps a little too short -- just as she is about to strike up, there, she cannot do it after all, an unwilling shake of the head tells us so and she breaks down before our eyes.

But then Fishbein stands up to refute the argument: 'The statute says that DNRs can be installed to find out about computer intrusions of their systems.

Mike rises from his chair and introduces her to Sarah, who stands up to shake her hand.

Mary stands up to be introduced, which is not technically necessary.

She is the only other human being in the universe actually, and when she stands up to shake his hand, his peripheral vision shuts down as if he has been sucking on a tailpipe.

Alba stands up to drink it, stands on tiptoe to achieve the best possible angle for sucking down a peanut butter milkshake.