The word 'unofficially' is a modern English formation built upon the adjective 'official,' which entered English via Old French from the Latin officialis, pertaining to duty or service (officium). The Germanic negative prefix 'un-' was attached to negate the sense, creating the adjective 'unofficial,' meaning not authorized or formal. Finally, the adverbial suffix '-ly,' of ancient Germanic lineage, was appended to describe the manner of an action. Thus, the term's logic flows from the concept of duty or authorized position, through its negation, to the adverbial form describing actions performed outside of formal channels.

Structure: un (not) + official (relating to authority) + ly (adverb suffix) - un: A prefix of Germanic origin (Old English) meaning "not," used to form negatives. - official: An adjective of Latin origin (from officium meaning "service, duty, office"), functioning as the core word denoting formal authority or status. - ly: A suffix of Germanic origin (Old English) used to form adverbs from adjectives.