Crossword puzzle clue "one might be used for checking"

One might be used for checking

One might be naked while checking the skies

Checking out a used car

"The ___ and Alize keep me pissy / Girls used to diss me / Now they write letters 'cause they miss me" (Notorious B.I.G. lyric name-checking his fancy champagne diet)

It's used when checking out, briefly

Checking, for one: Abbr.

One checking crossings

One checking out a place in planning a crime