enlistment vs allegiance

enlistment and allegiance both are nouns.

Word	Noun	Adjective	Verb	Adverb
enlistment	Yes	No	No	No
allegiance	Yes	No	No	No

As nouns, allegiance is a hypernym of enlistment; that is, allegiance is a word with a broader meaning than enlistment:

enlistment: the act of enlisting (as in a military service)
allegiance: the act of binding yourself (intellectually or emotionally) to a course of action

Other hypernyms of enlistment include commitment, dedication, loyalty.

enlistment (noun)	allegiance (noun)
the act of enlisting (as in a military service)	the act of binding yourself (intellectually or emotionally) to a course of action
a period of time spent in military service	the loyalty that citizens owe to their country (or subjects to their sovereign)