natty

Etymology 1

Originally slang, perhaps related to natural.

adj

1. (informal) Smart and fashionable.
   Anyway, while the creepy-video thing is under way there are also some scenes of Pullman looking very natty and East Village in all-black and jamming on his tenor sax in front of a packed dance floor (only in a David Lynch movie would people dance ecstatically to abstract jazz), […] 1997, David Foster Wallace, “David Lynch keeps his head”, in A Supposedly Fun Thing I'll Never Do Again, Kindle edition, Little, Brown Book Group

Etymology 2

Variant of knotty.

adj

1. (Jamaica, slang) Knotty.
   natty dreadlocks

Etymology 3

Clipping of natural + -y. Clipping of national + -y.

adj

1. (slang, sports, particularly bodybuilding) Natural, as opposed to steroid enhanced.
2. (slang) National.

noun

1. (slang, sports, particularly bodybuilding) Someone whose muscle gains are natural and not aided by the use of steroids.
2. (slang, sports) A national championship