That is to come, coming, future. Obsolete.

That comes, approaches, or arrives; esp. that is due to happen; that will be; future.

That is to be, or will be, hereafter. Often qualifying a noun, with the sense: The person or thing that is expected to be (what the noun denotes).

transferred or figurative. Of time, etc.

That is yet to be or to come; future. Esp. following nouns of kinship, as grandfather-to-be, wife-to-be; see also s.v. mother-to-be, n.

Unborn. Obsolete. rare.

To come, future. Now rare.

Coming, to come, future. Obsolete.

That rises up, in various senses.

Not yet arrived (at a place, or in time).

That will be (the person or thing designated); that aims at being, or is ready to be (someone or something). Cf. would-be, adj. n.

(un-, prefix1 affix 2.)

(un-, prefix1 affix 2b.)

Coming up.