Relating to or having the character of an announcement or proclamation; tending to announce.
From 'annunciation' + the adjective-forming suffix '-ive' (Latin '-ivus'), creating an adjective meaning 'of or pertaining to announcement.'
This adjective is so rare that it's almost never used—even 'annunciatory' is preferred—which shows how English sometimes creates grammatical forms that linguistically 'should' exist but never catch on in actual speech.
Complete word intelligence in one call. Free tier — 50 lookups/day.