Webster's Revised Unabridged Dictionary · 1913

Cad

Cad , noun

[Abbrev. from cadet.]

1.
A person who stands at the door of an omnibus to open and shut it, and to receive fares; an idle hanger-on about innyards. [English] — Dickens
2.
A lowbred, presuming person; a mean, vulgar fellow. [Cant] — Thackeray