If you are thinking of rekindling your relationship with an old flame, you came to the wrong place.What “backdating” is about is signing an agreement today with the intent that it be effective as of a prior date.A contract is made binding on the date that both parties intend that it is to come into effect, which is typically evidenced by both parties signing the agreement.There is no requirement for the signature to be witnessed.
The best practice is to make it clear that the effective date and the execution date are different. Things are usually implied though a course of business.
Or could doing so (backdating such a document) be considered fraud, forgery, or anything illegal, or even for some reason ethically or morally wrong?
It seems to me that it might be legal (assuming that I as the employee were willing to sign it) because as an employee I'd assume that some NDA was in place even if haven't signed one (so it's as if the agreement or meeting of minds was in place even before it was documented).
Simple contracts have a statutory "limitation period" of six years.
This means that a party to the contract must bring any claim for breach of that contract within 6 years of the breach taking place. Deeds are required by law in certain circumstances.