A word invented by actor Neil Patrick Harris during his appearance on The Late Late Show with Craig Ferguson in 2008.
adj.- (of a person or action) being particularly effeminate and flamboyant in a manner which might be likened to that of a swish or stereotypical gay man.
Neil Patrick Harris: You are just swishtastic tonight! You have been snapping and jumping around.
Craig Ferguson: I am swishtastic every night.
someone/something that is awesome, the best of the best, amazing.
Man that ninja was pretty swishtastic.