rationability
/ˌraʃ(ə)nəˈbɪlɪti/ /ˌraʃ(ə)nəˈbɪlɪti/Now rare
noun
The faculty of reason; the ability to be rational; (also more generally) accordance with reason, sensibleness.
Origin
Late 15th century; earliest use found in Speculum Sacerdotale. From classical Latin ratiōnābilitās quality of possessing reason, rationality (2nd cent. a.d. in Apuleius) from ratiōnābilis + -tās.