noun
lone monkey; stray monkey
Refers to a monkey that is alone, separated from its troop. Can be used literally or figuratively for a solitary person.
山の中で孤猿が一匹で木の実を食べていた。
A lone monkey was eating nuts by itself in the mountains.
彼は群れから離れた孤猿のような存在だ。
He is like a stray monkey separated from the group.