Lewis Short
(adjective) : portŭōsus, a, um, portus
* Full of or abounding in harbors, having many harbors: mare,Cic. de Or. 3, 19, 69: flumen Trinium,Plin. 3, 12, 17, § 106: pars Numidiae portuosior,Sall. J. 16, 5: navigatio minime portuosa,with no ports to run into,Cic. Fam. 6, 20, 1.—* Adv.: portŭōsē, with many harbors; only comp.: portuosius illic alveus Nili,with more harbors,Jul. Val. Rer. Gest. Alex. M. 1, 20 fin. Mai.
Charlton T. Lewis, Charles Short, A Latin Dictionary