The highest scoring word in Words With Friends is PERFECTLY with a total of 21 points.
Synonyms: superbly, superlatively, excellently, flawlessly, faultlessly, to perfection, without fault, ideally, wonderfully, marvellously, magnificently, sublimely, admirably, inimitably, incomparably, impeccably, immaculately, exquisitely, consummately, absolutely, utterly, completely, altogether, entirely, wholly, totally, thoroughly, fully, quite, in every respect