old chap
/ˌəʊl(d) ˈtʃap/Now chiefly British
noun
1Without necessarily connoting age, as a familiar form of address, chiefly to a man.
- Now generally considered old-fashioned or upper-class. Modern uses are frequently humorous or intended to characterize upper-class speech..
2An older man; frequently mildly disparaging.
Origin
Early 19th century; earliest use found in James Fenimore Cooper (1789–1851), novelist. From old + chap.