To be very old or elderly. In the Bible, Methuselah lived 969 years. I know I'll have a long life because my grandparents were as old as Methuselah when they died.Of course she can't use a smartphone, she's as old as Methuselah!
very old. (Of a person; refers to a biblical figure held to have lived to be 969. *Also: as ~.) Old Professor Stone is as old as Methusehah but still gets around with a cane.