for donkey's years

Idiom - British English - informal :
For a very long time
برای مدتی طولانی است که . . . . .
مدت مَدیدی است که . . . . .
به عنوان مثال :
She's been in the same job for donkey's years

منابع

• https://dictionary.cambridge.org/dictionary/english/donkey-s-years• https://www.ldoceonline.com/dictionary/donkey-s-years