Flab rhymes with:
colab, glab, lab, labbe, slab, ab, bab, babb, cab, colab, crab, crabb, crabbe, dab, drab, fab, gab, glab, grab, grabbe, jab, knab, knabb, krabbe, lab, labbe, mab, macnab, mcnab, mcnabb, nab, nabb, prab, prefab, rab, rabb, sabb, scab, schab, slab, stab, tab, tabb
Flab sounds like:
falb, falbo, falloff, falvey, falvo, felipe, filby, filip, filipa, filippi, filippo, fillip, flabby, flahive, flap, flavia, flavio, flip, flippo, flop, floppy, fluff, fluffy, flyby, followup, fullilove, fulop, fulp, fulvia