E. Cobham Brewer 18101897. Dictionary of Phrase and Fable. 1898.
Fulsome.
Ful is the Anglo-Saxon fúl (foulness), not ful (full); some is the affix meaning united with, the basis of something; as, gladsome mettlesome, gamesome, lightsome, frolicsome, etc., etc.
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No adulation was too fulsome for her [Elizabeth], no flattery of her beauty too great.Green: Short History of England, chap. viii. sec. 3, p. 376.