bearer of good tidings / bringer of good news
Active participle (faʿīl) of بَشَّرَ (Form II, to give good news). Noun: بِشَارَةٌ / بُشْرَى (good news/glad tidings). Related: بَشَرٌ (human being).
The balance of tabshīr (glad tidings) and indhār (warning) reflects the Quranic balance of hope (rajāʾ) and fear (khawf) in faith.