but for (someone)
Except for someone; if not for someone. But for the support of my friends, I never would have survived that difficult time.
but for someone or something
if it were not for someone or something. But for the railing, I'd have fallen down the stairs. But for the children, Mrs. Smith would have left her husband years ago.
but for
Except for, were it not for. For example, But for the afternoon shower, it was a perfect day, or But for the children, they would have gotten a divorce long ago. [c. 1200]
but for
Were it not for: except for: We would have reached the summit but for the weather.