A rear end that is exceptionally attractive, well-defined, or desirable according to the butt fad of the month.

Briefly, "the realization that each random passerby is living a life as vivid and complex as your own." Originally from the Dictionary of Obscure Sorrows, which has a lot more beautiful neologism definitions like this you might enjoy.

A small but really nice ass

It's really curvy and you just have lust for it.

Or when a girl just wears really tight skinny jeans that you can see her asscrack through them.

Someone who treats others ideas and opinions with scrutiny or sees the world in an extremely cynical and sarcastic view.

A cheap person or a over cautious person. Tight taken from 'Uptight'.

someone who is reluctant to spend money when they have no reason not too

combination of tight taken from uptight and ass taken from asshole. A tight ass is someone who could be uptight in a negative way.