retrenchment vs entrenchment

retrenchment and entrenchment both are nouns.

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

As nouns, entrenchment is a hypernym of retrenchment; that is, entrenchment is a word with a broader meaning than retrenchment:

retrenchment: entrenchment consisting of an additional interior fortification to prolong the defense
entrenchment: an entrenched fortification; a position protected by trenches

Other hypernyms of retrenchment include intrenchment.

retrenchment (noun)	entrenchment (noun)
the reduction of expenditures in order to become financially stable	an entrenched fortification; a position protected by trenches
entrenchment consisting of an additional interior fortification to prolong the defense