A hobby in which players wear military-style uniforms (sometimes this is not true) and wield realistic replicas of military weaponry. Essentially, it's non-lethal military warfare. Airsofting is all about realism, tactics, fun and awesome.
There's a few common misconceptions about airsoft. For one, it is not a game for 12 year olds, though I will admit, they often give all of us other players a bad name. It is not better or worse than paintball because it can't be statistically proven that one is better than the other; they're so different that you just can't say one is better. Besides, that's all a matter of opinion. Third, some paintballers may call airsofters wusses, but how many times can you say that a paintball has made you bleed? Sure, airsoft guns often don't, but you can still feel them when they hit you. Also, how much they hurt differs from person to person, and what gun the shooter is using. Some will hurt more than others. All of the BBs are the same size, but some of them are a different weight. They can be as light as .12 grams or as heavy as .25 grams; each weight producing different results in accuracy, speed and overall performance.
Note: Airsoft has a number of additional equipment, including landmines, grenades and plastic knives. As far as I know, paintball does not have any of these.
Airsofting often incorporates skill, tactics and teamwork.
Paintballing may apply these... very loosely that is.