専せん門もん外がい

noun which may take the genitive case particle 'no', noun

outside one's area of expertise; outside one's field

Used to indicate that something is not within one's professional or academic specialty. Often appears in the pattern 専門外の〜 or 専門外で〜.

• その質しつ問もんは私わたしの専せん門もん外がいです。

  That question is outside my area of expertise.

• 専せん門もん外がいの分ぶん野やについて話はなすのは難むずかしい。

  It's difficult to talk about a field outside one's specialty.