Relating to or of the nature of an announcement; serving to announce or proclaim.
From 'annunciation' + the adjective suffix '-ory' (Latin '-orius'), meaning 'pertaining to or characterized by announcement.'
This is the preferred form over 'annunciative'—and linguists aren't entirely sure why one suffix wins and another loses in English, but '-ory' words often sound more formal and established.
Complete word intelligence in one call. Free tier — 50 lookups/day.