Conductor
Commander
noun
If 指揮 is "command" or "lead" then someone who does those things is a commander, or conductor. Usually the kind that conducts an orchestra!
しきしゃ
The reading for this is the reading of 指揮 plus the on'yomi reading of 者.
どちらの指揮者もまだ来てないんだよ。
Neither commander has come yet.