What is the comparative form of word flat?

The comparative form of "flat" depends on what you're comparing.

* If you're comparing flatness, the comparative form is "flatter"**. For example, "This pancake is flatter than the other one."

* If you're comparing how flat something is pressed against a surface, the comparative form is "flatter"**. For example, "He pressed his hand flatter against the window."

* If you're comparing the lack of interest or excitement, the comparative form is "flatter"**. For example, "The party was flatter than I expected."

It's important to consider the context to choose the right comparative form.