Overpass rhymes with:
underpass, boardingpass, bumpass, bypass, trespass, underpass, worldpass, airgas, amerigas, bluegrass, boardingpass, bumpass, bypass, eelgrass, energas, eyeglass, fiberglas, fiberglass, hourglass, jackass, landmass, outclass, piepgras, plexiglas, plexiglass, sassafras, serfass, shortgrass, snodgrass, spyglass, sunglass, tallgrass, trespass, underclass, underpass, upperclass, worldpass, yankass
Overpass sounds like:
oberbeck, overbaugh, overbeck, overbook, overbooks, overpasses, overpeck, overviews