stand up phrasal verb ( see also ↑ stand )
1 . to be on your feet, or to rise to your feet ⇨ stand-up :
I’ve been standing up all day.
Stand up straight and don’t slouch!
Jim stood up stiffly.
2 . [always + adverb/preposition] to stay healthy or in good condition in a difficult environment or after a lot of hard use
stand up to
Most of the plants stood up well to the heat.
3 . to be proved to be true, correct, useful etc when tested
stand up to/under
The memoirs stand up well to cross-checking with other records.
Without a witness, the charges will never stand up in court (=be successfully proved in a court of law) .
4 . stand somebody up informal to not meet someone who you have arranged to meet:
I was supposed to go to a concert with Kyle on Friday, but he stood me up.
5 . stand up and be counted to make it very clear what you think about something when this is dangerous or might cause trouble for you