Definition of "undeserver"

Let me tell you, Cassius, you yourselfAre much condemn'd to have an itching palm;To sell and mart your offices for goldTo undeservers.

1599 (first performance), William Shakespeare, “The Tragedie of Iulius Cæsar”, in Mr. William Shakespeares Comedies, Histories, & Tragedies […] (First Folio), London: […] Isaac Iaggard, and Ed[ward] Blount, published 1623, [Act IV, scene iii]