What is another word for not crooked?

Here are some words that could be used to describe something that is not crooked, depending on the specific context:

General:

* Straight

* Aligned

* Level

* Even

* True

* Upright

* Vertical (if referring to an angle)

* Horizontal (if referring to an angle)

More specific:

* Symmetrical (if referring to balance and evenness of shape)

* Regular (if referring to consistent form)

* Unbent (if referring to something that was previously bent)

* Unwarped (if referring to something that was previously warped)

Figurative:

* Honest (if referring to someone's character)

* Fair (if referring to a situation or process)

The best word to use will depend on the specific situation and what you are trying to convey.