improbulus (inpr-) adj. dim.
improbus, somewhat wicked, a trifle impudent , Iu.
imprŏbŭlus (inpr-), a, um, adj. dim. [improbus], somewhat wicked , Juv. 5, 73. ...
A New Latin Dictionary by Charlton T. Lewis Ph.D. and Charles Short, LL. D.