〜ぬきで／〜ぬきに

冗談ぬきで、本当の話です。

Jōdan nuki de, hontō no hanashi desu.

Joking aside, this is a real story.

ぬきで removes something; 冗談ぬきで has set into a fixed phrase

朝食ぬきで出かけるのは体に悪いです。

Chōshoku nuki de dekakeru no wa karada ni warui desu.

Going out without breakfast is bad for you.

It is for leaving out something that should be there

形容詞的に使うときは ぬきの になります。

Keiyōshiteki ni tsukau toki wa nuki no ni narimasu.

Modifying a noun it becomes ぬきの.

わさびぬきの寿司 is the most useful line when ordering