Used to denote when a comment has gone over someone's head. Onomatopoetic to the sound of an object moving past you at an accelerated pace.
Made even funnier when saying "woosh" also makes no sense to
the person that earned the "woosh", thus making a combo that cannot be
countered until combo-broken.
Sometimes typed as /woosh in an MMORPG setting, as if something making no sense to someone was an emote of some kind.