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.
This is a term mostly used by those involved with Wheel of Fortune. It means fantastic, but the "fan" is changed to "spin", referencing the wheel in the popular game show. Pat Sajak, the host, has said this phrase a few times, which is how it stuck with the audience.
person 1: mate. i see you got a new car?
person 2: yes. this is true. its nice. i like it.
person 1: its better than nice mate. i'll tell you what it is. its SWANKTASTIC!