indulgence vs softness

indulgence and softness both are nouns.

Word	Noun	Adjective	Verb	Adverb
indulgence	Yes	No	No	No
softness	Yes	No	No	No

As nouns, softness is a hyponym of indulgence; that is, softness is a word with a more specific, narrower meaning than indulgence:

indulgence (noun)	softness (noun)
the act of indulging or gratifying a desire	the property of giving little resistance to pressure and being easily cut or molded
foolish or senseless behavior	a sound property that is free from loudness or stridency
the remission by the pope of the temporal punishment in purgatory that is still due for sins even after absolution	a disposition to be lenient in judging others
an inability to resist the gratification of whims and desires	acting in a manner that is gentle and mild and even-tempered
a disposition to yield to the wishes of someone	the trait of being effeminate (derogatory of a man)
	the quality of being indistinct and without sharp outlines
	a visual property that is subdued and free from brilliance or glare
	a state of declining economic condition
	poor physical condition; being out of shape or out of condition (as from a life of ease and luxury)
	the quality of weather that is deliciously mild and soothing