Select the most appropriate one-word substitution for the given group of words.

A person eighty years of age

Octogenarian

The most appropriate one-word substitution for "a person eighty years of age" is octogenarian.

• Octogenarian means a person who is between 80 and 89 years old.
• Heptagenarian means a person who is between 70 and 79 years old.
• Nonagenarian means a person who is between 90 and 99 years old.
• Eightiest is not a real word.