1
general::
A direction or order to hold one's hands high, as in Hands up or I'll shoot! This imperative is used by police officers and criminals so that they can see if someone is holding a weapon. [Second half of 1800s]
American Heritage Idioms
2
general::
Phrase(s): Hands up! [and] Stick ’em up!; Put ’em up!
Raise your hands in the air; this is a robbery! (Underworld and Old West.) • Hands up! Don’t anybody move a muscle. This is a heist. • Stick ’em up! Give me all your valuables.
McGrawhill's American Idioms And Phrasal Verbs