Not Defined option not displaying

Hello,

We have some products that have Not Defined as a product option. Unfortunately this does not show on the front end, is there a workaround for this so it can show Not Defined or N/A?

https://www.ads-software.com/plugins/woocommerce/

edit: I forgot to say the option is Not Defined because it’s imported from Point OF Sale Software that requires the user to enter a value for color. Some of which were entered as Not Defined and can’t be changed. If there was a way to show that “Not Defined” option that would be great so we don’t have to enter thousands of product options again. Thanks