It's actually referred to as the "Incontestable Clause" in your life insurance policy.
The Incontestable Clause section in a life insurance policy states that after the life insurance policy is In Force two years, the life insurance company cannot void it because of misrepresentation or concealment by the insured person in obtaining the life insurance policy.
So, if some one where to apply for and be accepted for life insurance after lying on the application, and two years has passed since the person has become insured, the life insurance company cannot void the life insurance coverage due to the lie, or misrepresentation.
And, if the insured dies more than two years after becoming insured for the life insurance, the insurance company would be required to pay out the death benefit to the insured's beneficiary, subject to any exclusions in the policy.