Guilfoil rhymes with:
foil, foyle, boil, boyle, britoil, broil, coil, coile, coyle, croyle, doyle, embroil, foil, foyle, gatoil, hoyle, lukoil, moyl, moyle, o'boyle, oboyle, oil, oleoyl, recoil, roil, royle, soil, spoil, statoil, toil, uncoil
Guilfoil sounds like:
gleeful, gleefully, glibly, global, globally, guilfoyle, gullible