Ginchy morphed into boss, morphed into groovy, morphed into bad, rad, cool, bitchin', sick, etc. etc. (there are likely another hundred words). As Kookie said, "Baby, you're the ginchiest" the best.
"wow, that's ginchy", on hearing 'some velvet morning' when you were 18 in 1989 (god, I loved being young) when all you were use to before seemed so ordinary. Ahh, like I say, sweet.
Used to describe someone, who thinks they are cool or what they are doing is cool, in a sarcastic and negative way.
Commonly used by Americans to describe other Americans who deliberately adopt habits of other cultures because they want others to see how "cultured" they are.
Ex. Usings chopsticks (we all know forks, spoons, and knives work better).