To stand up is to rise to your feet. From sitting to standing, in one movement.
It has several useful extensions. Standing up for somebody means defending them, standing up to somebody means refusing to be intimidated, and standing somebody up means failing to arrive for a date, which is one of the least forgivable things in the language. An argument that stands up is one that survives examination. Stand-up as a noun is comedy performed alone at a microphone.
1phrasestand upTo rise to your feet.
“Everybody had to stand up when the judge came in.”
2phrasesurviveTo survive examination.
“The claim will not stand up in court.”
Also accepted in games: get up
Old English
standan up
Middle English
standen up
English, today
stand up
From Middle English standen up, from Old English standan up; equivalent to stand + up. Compare Old Norse standa upp.
Etymology from Wiktionary, CC BY-SA