The word 'tunelessly' is built upon the core concept of a 'tune', which traces back to the Greek 'tonos', signifying tension and, by extension, a musical pitch. The addition of the Old English suffix '-less' transforms it into an adjective meaning "devoid of a tune." Finally, the adverbial suffix '-ly', also of Old English origin, specifies the manner of an action. Thus, the literal progression from "tone" to "without a tone" to "in a manner without a tone" clearly illustrates the word's logical construction for describing an action performed without melody or musicality.

Structure: tune (melody) + less (without) + ly (in the manner of) - tune: From Old English 'tune', meaning a musical sound or note. Origin: Latin 'tonus' (a sound, tone), from Greek 'tonos' (tension, tone). - less: A suffix forming adjectives meaning "without, free from". Origin: Old English '-lēas', from a Germanic root meaning "free, loose". - ly: A suffix forming adverbs from adjectives, meaning "in a specified manner". Origin: Old English '-līce', from Germanic.