It's possible you are thinking of the prefix "grat-," which means "pleasing" or "thankful."
Here are some examples of words with the prefix "grat-":
* Gratitude: A feeling of thankfulness and appreciation.
* Gratis: Free of charge.
* Gratify: To please or satisfy.
* Gratuitous: Unnecessary or unwarranted.
If you have a specific word in mind, please let me know so I can help you understand its meaning!