greetings - What does うぃーす mean?

What does うぃーす exactly mean? (I vaguely hear it when people greet each other.) How is it different from other greetings?

Is it correct to write it as うぃす too?

How to properly type it on a Macbook? The い is a smaller font, and I don't know how to type ー.

Answer

"うぃーす" is a ultra-shortened greetings of, maybe おはようございます or something. "おっす" is one of the variations. Although the etymology is not clear, these are used in several ways.

1. 
   

   A sluggish, slow "うぃーっす" is a greeting used between young, mainly male, close friends. I think this is what @Sjiveru described, as something like "yo". People use this when they feel pronouncing "おはよう(ございます)" is too long and bothering.

   
   


2. 
   

   A short, vigorous, strong "うぃっす!" or "おっす!" can be a polite greeting in certain sport clubs/teams. You may be safe to say "うぃっす！" even to your seniors or advisers (But this greatly depends on the team you belong to). In such cases, the strength of your greetings determines the level politeness rather than what is actually said as a word. I think people use this because pronouncing "おはようございます" is too complicated to say out loudly. This is also something repeated almost meaninglessly in response to someone's speech, like "yes (sir)."

   
   

I can't say "うぃす" is incorrect, especially when it's used in the second situation. This is a shortened/altered form, so basically you can write this in whatever way you like. But "うぃーっす", "うぃーす" or "うぃっす" is more common.