You should tell the professor or the guide about the delay of the project otherwise it will create trouble in the coming time but if you tell the situation to your supervisor it will give you leverage to complete the project in a delayed situation.
You should focus on producing furnished work to show the quality of your assignment and you should also tell your professor about the quality of your assignment so that your guide can understand the reason for the delay in the project. You should assure the guide about the delay that you will not commit this kind of mistake in the future again. There are many reasons that can be stated as the late assignment hacks in a delayed situation.
You can pretend that you were not well because of some medical issues so that you can save yourself from any kind of unforeseen trouble in the future.
You can also say that you have lost your documents so you have to prepare this assignment again. This is how you can save yourself from any kind of unwanted trouble.
You can also say that your grandparents have passed away that is why you were engaged at your home in completing the tradition.
You can have one more idea that you are the eldest son of your family. That is why you have been given the responsibility to care for your younger siblings; hence you were not able to complete your task at the given deadline.
You can also have one more reason that you have forgotten the assignment at your grandparent's home.
If you are a girl you can have one more good excuse as you were having your menstruation in that period of time.
You can state to your guide that you were not able to manage finances at that period of time. That is why you did not write the assignment. This is how you can get rid of any unforeseen trouble.