[possibly from OED chalk mark or score made with chalk in various games, i.e. something is so firmly planned that it may as well have already happened; cf. also DAE chalk the real or proper thing; DARE idem, something outstanding, fashionable of good quality] phr. 1. That's inevitable; a foregone conclusion (older adults). (Exuma)
2. That's great (in agreeing to a social arrangement) (youth slang). = BOUF 4 (Black)
chalk up [W3 to achieve; cf. CHALK 2] v. phr. to do (something) very well (youth slang): Gal, I chalk up on that test- I know I get a 'A' (Nassau).