splurge vs indulgence

splurge and indulgence both are nouns.

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

As nouns, indulgence is a hypernym of splurge; that is, indulgence is a word with a broader meaning than splurge:

Other hypernyms of splurge include humoring, humouring, indulging, pampering.

splurge (noun)	indulgence (noun)
any act of immoderate indulgence	the act of indulging or gratifying a desire
an ostentatious display (of effort or extravagance etc.)	foolish or senseless behavior
	the remission by the pope of the temporal punishment in purgatory that is still due for sins even after absolution
	an inability to resist the gratification of whims and desires
	a disposition to yield to the wishes of someone

splurge (verb)	indulgence (verb)
be showy or ostentatious
indulge oneself