imperscriptible (adj.) Look up imperscriptible at Dictionary.com
"unrecorded, without written authority," 1792 (used almost exclusively with right (n.)), from French imperscriptible, from assimilated form of Latin in- "not, opposite of" (see in- (1)) + perscribere "to write down." Earliest in English in reference to the French evolution. Spelling imperscriptable attested from 1827.