softly vs lightly

softly and lightly both are adverbs.

Word	Noun	Adjective	Verb	Adverb
softly	No	No	No	Yes
lightly	No	No	No	Yes

As adverbs, softly and lightly are synonyms defined as:

Other synonyms of softly include gently.

softly (adverb)	lightly (adverb)
with low volume	with little weight or force
with little weight or force	indulging with temperance
used as a direction in music; to be played relatively softly	with few burdens
in a manner that is pleasing to the senses	in a small quantity or extent
	with indifference or without dejection
	to a slight degree
	without good reason