can't help but; compelled; irresistible urge
Describes a situation where one is driven by an inner compulsion or unavoidable circumstances, not by rational choice. Often used with verbs like する or なる to express doing something against one's will or better judgment.
He couldn't help himself and quit the company.
I have no choice but to be absent.
Kanji spelling using 止む; less common but still encountered.
Rare kanji form using 已む; it is rarely used.
From the verb 止む (to stop) in a classical negative form, literally 'without being able to stop'. The repetition やむにやまれず intensifies the meaning of being unable to cease or resist.