I have been watching many American movies and it seems they often say "hold up" to stop someone from proceeding a next action.
See this scenarios, a group of criminals are pointing their guns at a bystander and about to fire, but their leader says "hold up".
However, "hold on" seems to be used more in Australian and British English but I am not sure.
Can we say "hold on" to stop someone from proceeding a next action?
Both "hold on" and "hold up" can have the same strict definition, though the intensity and register vary slightly. (The two phrases each have other uses that differ in other ways, which we don't really need to discuss in this answer)
For this particular usage, "hold up" is a bit more forceful, and a bit less formal, than "hold on".
If a region tends to use one form more often than another, it is more likely to be related to a cultural/regional preference for certain registers rather than an actual dialectal difference.
AmE speaker from the PNW here.
I would say that the two terms are similar, but "hold up" has a connotation of "stop", while "hold on" has a connotation of "pause".
If I say "hold on" to someone, it's likely that I will later ask them to continue from where they left off, or that I will later continue from where I left off.
If I say "hold up" to someone, it's likely that I will suggest a different course of action, or at least a re-examination of the goals or presumptions that prompted the original course of action.
"Hold up" is unusual in British English, although it is well-understood due to exposure to American media where it is common. As I understand it, both "hold on" and "hold up" are common in American English.
In this particular instance though, I'd probably say "hang on" or "hang on a minute" instead of either.
I would say that “hold on” and “hold up” are both used in AmE, which is what I speak, but with subtle differences in context and connotation. “Hold up” is certainly more colloquial of a term, and I tend to associate it with a more forceful and sometimes negative tone.
For instance, “hold on” can be used in a variety of contexts: if your mother is speaking on the phone when you try to talk to her, she may say, “hold on.” It would be highly unusual for her to say “hold up,” which may come across as oddly casual or unnecessarily short. The phrase “hold on” is more generally applicable and flexible in terms of tones it can carry.
In British English "hold up" would be most often used in a robbery, often at gun point, like your example.
"hold on" would be used in other situations where you want someone to stop what you are doing, often to confer before moving on to the next step.
In the English-speaking Caribbean, where there is a blend of both British and American influence, the usage of each expression is not strict with respect to the situation in which each term is used. However, generally, depending on which island you are on, "hold up" would more often be used if someone was saying or doing something you did appreciate and you wanted to respond whereas "hold on" would be used if you were asking someone to wait for a bit whether you were on the telephone or standing at the counter in a pharmacy. The implication is that "hold up" will be quicker used to counter an aggressive situation/person/animal than "hold on"...
I think they are technically interchangable. They share the same definition, but "hold up" is for a bit extreme cases. Like, stop immediately. "Hold on" is a bit more relaxed and for relaxed cases, like you're searching for the key to your car and you're telling your (friend) to not go in yet.
As a native British English speaker, I would never use "hold up" to mean "hold on" or "hang on" in that context.
Here in the UK, I hear those as very different, although most people would still understand if they were swapped round. I do think many US Americans will hear the two as interchangeable.
(I'm assuming "… proceeding a next action…" here means "proceeding with an action." Is that right?)
I hear "hold on" as "stop what you're doing" just as yes, we say "hold on" to stop someone from proceeding a next action. "Hold on" can be an expression complete in itself.
I hear "hold up" as "interrupt or delay something else", as for instance "Hold up the traffic (until the procession has passed)". That works only with a stated object.
That the criminals pointing their guns at a bystander are carrying out a "hold up" is a co-incidence, isn't it? Similarly, this doesn't touch on "You hold up that end of the shelf while I fix the bracket" or "Grab something solid and hold on."
