geezer(n = noun.person) - a man who is (usually) old and/or eccentric;
is a kind of adult male, man
Derived form noun geezerhood₁

   A queer old fellow; an old chap; sometimes, an old woman. [Webster 1913 Suppl.]

geezer, n. sl. a person, esp. an old man.

Etymology:
dial. pronunc. of guiser mummer

old geezer