Learn how to say Missive correctly in English with this tutorial pronunciation video.
Oxford dictionary definition of the word missive:
a letter, especially a long or official one:
yet another missive from the Foreign Office
Scots Law a document in the form of a letter exchanged by the parties to a contract. See also conclude missives at conclude.
late Middle English (as an adjective, originally in the phrase letter missive): from medieval Latin missivus, from Latin mittere ‘send’. The current sense dates from the early 16th century