What is the antonym for ketchup?

There isn't a true antonym for ketchup in the sense of a word that means the exact opposite. However, depending on the context, you could consider some options:

Based on flavor/purpose:

* Mustard: A common condiment, often used as a contrasting flavor to ketchup.

* Mayonnaise: Another popular condiment, typically used on sandwiches and salads, offering a different flavor profile.

* Relish: A sweet or savory condiment made from chopped vegetables, often used on hot dogs and hamburgers.

* BBQ Sauce: A thick sauce with a smoky flavor, often used for grilling and barbecuing.

Based on function:

* Nothing: If you're talking about simply not using ketchup, the opposite is just not using it.

* Alternative: This is a broader term that could refer to any condiment or topping used instead of ketchup.

Ultimately, the "antonym" for ketchup depends on what aspect of the word you're trying to contrast.