imprŏbābĭlis (inpr-), e, adj. [2. inprobabilis], not deserving of approbation, objectionable, exceptionable (not ante-Aug.; for in Cic. Ac. 2, 11, 33, the correct read. is probabilem; cf. Cic. Off. 2, 2): rationes, Cels. praef. med.: motus animi, Sen. Ep. 75 med.: factum per se improbabile, Quint. 7, 4, 7: argumentum, Plin. 4, 13, 27, § 93: non improbabilis mos, Dig. 50, 14, 3.
Adv.: imprŏbābĭlĭter, objectionably: objecta non improbabiliter, Sid. Ep. 1, 11 med.