Lewis Short
(adjective) : mūnis, e, cf. munus
* Ready to be of service or to oblige, obliging (ante-class.): dico ejus pro meritis gratum me et munem fore,Plaut. Merc. prol. 105: munifici munesque viri, Lucil. ap. Non. 23, 15; cf.: munem significare ... officiosum: unde e contrario immunis dicitur, qui nullo fungitur officio, Paul. ex Fest. p. 143 Müll.
Charlton T. Lewis, Charles Short, A Latin Dictionary