RhymeZone: unnoble definitions

Definitions of unnoble:

adjective: (dated, chiefly pre 1900) Not of noble rank.
adjective: Not noble; ignoble; base.
adjective: (metallurgy) Of a metal, being at the lower end of the electrochemical series, i.e. oxidising readily.
verb: (transitive) To make (someone or something) no longer noble

(Definitions from Wiktionary)