filthy lucre vs net income

filthy lucre and net income both are nouns.

Word	Noun	Adjective	Verb	Adverb
filthy lucre	Yes	No	No	No
net income	Yes	No	No	No

As nouns, net income is a hypernym of filthy lucre; that is, net income is a word with a broader meaning than filthy lucre:

filthy lucre: shameful profit
net income: the excess of revenues over outlays in a given period of time (including depreciation and other non-cash expenses)

Other hypernyms of filthy lucre include earnings, lucre, net, net profit, profit, profits.

filthy lucre (noun)	net income (noun)
shameful profit	the excess of revenues over outlays in a given period of time (including depreciation and other non-cash expenses)