The word 'unenforced' is a modern English formation built upon the verb 'enforce,' which entered the language from Old French enforcier ("to strengthen, force"). The French term itself combined the intensive prefix en- (from Latin in-) with the root related to force (force, from Latin fortis). The prefix 'un-' is a native English negative, added to create the opposite meaning. Thus, the literal morphemic sequence "not + cause to be + compelled" logically constructs the modern abstract sense of a rule or law that is not actively made effective or obeyed.

Structure: un (not) + en (cause to be) + forced (compelled) - un: A prefix of Germanic origin (Old English un-), meaning "not." It functions as a negative particle. - en: A prefix of French and Latin origin (from Latin in-), meaning "to cause to be, put into." It functions as a verb-forming prefix. - forced: The past participle of the verb "force," from Old French forcer, from Vulgar Latin fortiāre, from Latin fortis meaning "strong." It functions as the core lexical element meaning "compelled."