Naff rhymes with:
assaf, behalf, braff, calf, carafe, chaff, fraph, gaf, gaff, gaffe, giraffe, graf, graff, graph, haff, half, laff, laugh, paff, pfaff, raf, raff, scaff, schaff, shaff, sielaff, skaff, staff, staph, taff, taffe, unitaf, yaffe
Naff sounds like:
naab, nab, nabb, nabi, nabob, naef, naeve, naify, naive, nambi, namibia, namphy, nanobaby, nap, napa, napea, napp, nappa, nappi, nappo, nav, nava, nave, navy, neave, neeb, neef, neff, nepa, nephew, neuhoff, neva, neve, neveau, neveu, newbie, newby, newwave, nib, nibbe, niehoff, nimby, nineveh, nip, nipp, nippy, nobbe, nobuo, nope, nouveau, nov, nova, novey, novi, novia, novo, novoa, novy, nub, nuevo, numb, nuova, nuovo, nymph