other than; excluding; without
A formal, somewhat literary expression used to single out someone or something as the only option. Often follows a noun or noun phrase and is used in patterns like ～をおいてほかにない (there is no one/nothing else but ~).
There is no one else but him who can be entrusted with this job.
この問題を解決できるのは、あなたをおいてほかにはいません。
There is no one but you who can solve this problem.