Wei and Jin scholars liked to wave a deer-tail whisk while talking philosophy.
Tips
history
麈 is not used independently in modern Chinese. It named a kind of elk; its tail-hair made the 麈尾 whisk that Wei-Jin scholars waved during 清谈 (pure-talk philosophical debate), so the word survives mainly as a cultural reference.
register
Classical / literary only — seen in old texts and cultural notes, not in everyday speech.
Tucked at the lower right, 主 supplies the sound zhǔ directly with no tone shift. It contributes no 'master' meaning here — it is the sound tag inside the deer radical.