old boy

Noun old boy has 3 senses

• old boy(n = noun.person) old man - a familiar term of address for a man;
is a kind of adult male, man

• old boy(n = noun.person) - a vivacious elderly man;
is a kind of golden ager, old person, oldster, senior citizen

• old boy(n = noun.person) - a former male pupil of a school;
is a kind of alum, alumna, alumnus, grad, graduate