Is it okay to submit a paper from a master's thesis without informing the advisor?

Under no circumstances can it be ok to submit with his name on it but without his explicit consent. This wouldnt be ok if he'd be enthusiastic about your research, and if he is not particularly fond of it, this will quite certainly end badly.

If you are confident that your advisor did not contribute to the planned submission in a meaningful way, the default course of action should be to sent him a message informing him of the planned submission and thanking him for the guidance received. That way, if he disagrees on not having contributed, there is a chance to fix stuff before they blow.

Your first priority should be to finish your degree. Without more information, I don't know whether submitting alone would jeopardize that or not, so find out first. Make sure you understand the rules at your university around theses and publication.

Also consider what is considered appropriate in your field. I assume it is economics, but I have no knowledge whether it is appropriate for a student to publish without his or her advisor. In some fields it would be fine. In others, it would be considered a transgression.

Your advisor probably knows all of this. If personalities don't suggest otherwise it would probably be best to ask him how you should submit your work to the conference and whether that would cause any difficulties.

My best guess is that he would say ok, but if not, consider what else he says in light of the first priority - completion.

At the level of a master's degree, a joint paper with your advisor still has value, so don't rule that out completely if it is the common practice of your field, or if it would help advance your cause.

But you are probably the best judge here to evaluate both the requirements of your university and the relationship with the advisor.

I am based in Germany and had a similar problem recently. As it turns out, my university had a guideline which explicitly says that you are the sole author of you bachelor's / master's thesis, since everything else (e.g. co-authorship of your advisor) would be in conflict with the fact that the thesis should be an assessment of ONLY the student's capabilities. I suggest that you find out if your university has a guideline for such issues.

Having your advisor on board might have advantages later, i.e. when it comes to writing rebuttals or preparing the presentation.