A standard way to turn an adjective into an adverb is to add “-ly”: “glad” becomes “gladly” and “huge” becomes “hugely.” But when the adjectival form itself already ends in “-ly” it often feels awkward to create an adverbial form. If someone acts in a friendly manner do they behave “friendly” or ”friendlily”? Did your daughter perform her dance solo “lovely” or “lovelily”? Most of us sense that these forms, though legitimate, are awkward, and try to avoid constructions that seem to require them. There are a variety of ways to do this: someone is friendly, a daughter gives a lovely performance.
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