play-by-play announcer; on-the-scene commentator
Abbreviation of 実況アナウンサー. Used for sports broadcasters or live reporters who provide real-time commentary.
See also: 実況アナウンサー
He is famous as a soccer play-by-play announcer.
The on-the-scene commentator's vivid voice livened up the match.
Clipping of 実況アナウンサー (jikkyō anaunsā), itself from 実況 (jikkyō, 'live broadcast') + アナウンサー (anaunsā, 'announcer').