Old
A geriatric You call them elderly or an elder.
A "septuagenarian" is a person who is 70 through 79 years old.
A person that is very old is commonly referred to as elderly or a senior citizen.
Old
quinquagenarian
A one-hundred-year-old person can be called a Centenarian.
A person who is 60-69 years old is called a sexagenarian.
forty five year old person
A Monumental Mason
hexagenarian
A 70-year-old individual is commonly referred to as a septuagenarian.