When it is pronounced excuse to rhyme with loose a noun and means?

There isn't a word that rhymes with "loose" and means "excuse" in the way you're describing.

It's likely you're thinking of the word "excuse" itself, which is pronounced with the "excuse" rhyme.

It can act as a noun, meaning:

* A reason given to explain or justify a fault, offense, or omission.

* Example: "He gave a flimsy excuse for being late."

* A reason given for being unable to do something.

* Example: "I'm sorry, I can't make it. I have a prior excuse."

Let me know if you were thinking of something else!