Grievous rhymes with:
beavis, chivas, beavis, bodhisattvas, canvas, canvass, chivas, corvus, covas, crevice, davis, davis', disservice, gervase, gustavus, holvis, holvis', jarvis, mischievous, navas, nervous, novice, pelvis, provus, service, synovus
Grievous sounds like:
garbacz, garbage, garp's, garps, gearbox, gearboxes, geographic, geographic's, gerbasi, gerbig, gervais, gervase, gervasi, gervasio, giraffes, graboski, grabowski, grabs, grabski, graffius, grapage, grapes, graphic, graphics, graphics', graphs, graves, graves's, gravies, gravois, grbavica, greaves, grieves, griffey's, griffis, gripes, grips, grivas, grooves, groppy's, group's, groupies, groups, groups', grove's, groves, grubaugh, grubbs, grubs, gurevich