What is a homophone for large rock?

There isn't a perfect homophone for "large rock" in the sense of a single word that sounds the same but has a different meaning. However, you could use:

* "lark" - This is a homophone for "lark" (a type of bird), but it could be used in a metaphorical sense to describe a large, playful rock.

* "rock" - While it's the same word, you could use it in a different context to sound like "large rock." For example, "The band played a rock concert."

* "large rock" - This might sound obvious, but if you're writing dialogue or something where you want a specific emphasis, you could simply repeat the phrase.

It really depends on the context of what you're trying to achieve!