A person that is very old is commonly referred to as elderly or a senior citizen.
A person who is 40 years old is commonly referred to as being in their forties.
Mzee or Mkongwe (the latter used for very old people). These are nouns derived from adjectives, -zee and -kongwe, used to describe people: Mtu mzee (old person), mtu mkongwe, very old person. The noun is simply dropped, as in German Der Alte. Swahili does not have feminine and masculine versions of nouns. Mzee, however, is most often used of a man: a woman is mama mzee; it would not be wrong to call her mzee but might confuse. plurals: wazee and wakongwe.
a geezer a granny an antique
A person between 50 and 60 years old is commonly referred to as "middle-aged."
You can refer to a person aged 20-29 as a young adult.
A geriatric You call them elderly or an elder.
(Land) Lord. Wealthy.
They are probably looking for Ent. They were very old creatures that looked like trees.
A very very confused person.
Old
you call them wealthy.
a banchee or a VERY VERY VERY annoying person with terets or ADD
A Senior Citizen?
A genius.
Happy or a very lighthearted person.
a very intelligent person.
Parsimonius A miser "schrooge"