'Credibleness' definitions:

Definition of 'credibleness'

From: WordNet
noun
The quality of being believable or trustworthy [syn: credibility, credibleness, believability] [ant: incredibility, incredibleness]

Definition of 'Credibleness'

From: GCIDE
  • Credibleness \Cred"i*ble*ness\, n. The quality or state of being credible; worthiness of belief; credibility. [R.] --Boyle. [1913 Webster]