mǒu​rén

someone

某人 mǒu​rén
someone pronoun
a certain person; someone or some people whose names are unknown or do not need to be mentioned

I think someone's a little nervous.

I
(literary) used after one's own surname to refer to oneself in the third person

Frequency

Movie subtitles
34.9 per million appears in 15% of films
Written text
31.7 per million

Sources