economy vs retrenchment

economy and retrenchment both are nouns.

Word	Noun	Adjective	Verb	Adverb
economy	Yes	No	No	No
retrenchment	Yes	No	No	No

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

economy: an act of economizing; reduction in cost
retrenchment: the reduction of expenditures in order to become financially stable

Other hyponyms of economy include curtailment, downsizing, economy of scale.

economy (noun)	retrenchment (noun)
an act of economizing; reduction in cost	the reduction of expenditures in order to become financially stable
frugality in the expenditure of money or resources	entrenchment consisting of an additional interior fortification to prolong the defense
the efficient use of resources
the system of production and distribution and consumption