credibility Copy link • credibility: no word nearer than fĭdes or auctoritas: what authority and c. can the letter have? quam habere auctoritatem et quam f. litterae possunt? Cic.: a book of well-ascertained c., liber spectatae f., Gell. Phr. to give an appearance of c. to their story, *quo veris similiora redderent dicta sua: to prove the c. of a history, *historiam veri similem esse demonstrare, probare: a book concerning the c. of Roman history, *liber de fide atque auctoritate Romanae historiae scriptus: have these things any c., *haeccine talia sunt ut iis fides sit habenda?