Missive

a.	1.	Specially sent; intended or prepared to be sent; as, a letter missive.
	2.	Missile. Letters missive letters conveying the permission, comand, or advice of a superior authority, as a sovereign. They are addressed and sent to some certain person or persons, and are distinguished from letters patent, which are addressed to the public.
n.	1.	That which is sent; a writing containing a message.
	2.	One who is sent; a messenger.

Noun

1.

missive - a written message addressed to a person or organization; "mailed an indignant letter to the editor" Synonyms: letter

address, aerogram, aerogramme, air letter, airmail letter, business letter, chain letter, correspondence, cover letter, covering letter, crank letter, dead letter, dead mail, destination, document, encyclical, encyclical letter, epistle, fan letter, form letter, invitation, letter, letter of intent, line, mail, name and address, open letter, pastoral, personal letter, postscript, PS, round robin, text, textual matter