Unforgivable rhymes with:
forgivable, forgivable, forgivable, forgivable, forgivable, livable, unlivable, achievable, approvable, believable, conceivable, drivable, forgivable, immovable, inconceivable, livable, lovable, microwavable, movable, observable, provable, receivable, removable, solvable, survivable, unbelievable, unlivable, unsolvable
Unforgivable sounds like:
unbreakable, unenforceable, unforeseeable