The word 'unsteadily' is built upon the core Germanic adjective 'steady,' which traces back to Old English stæððig, itself derived from the noun stæð meaning "a shore, bank, or foundation"—a place of stability. The negative prefix 'un-,' one of the most common and ancient in English, directly reverses this core meaning to indicate a lack of firmness. Finally, the adverbial suffix '-ly,' originating from the Old English -līce (meaning "body, form, like"), transforms the adjective into a descriptor of manner. Thus, the literal morphemic construction "not + firm + in the manner of" elegantly conveys the modern abstract sense of moving or acting in a shaky, irregular, or insecure way.

Structure: un (not) + steady (firm) + ly (adverb suffix) - un: A prefix of Germanic origin (Old English un-), meaning "not." It functions as a negative or reversing particle. - steady: An adjective of Germanic origin (from Old English stæððig, "firm, stable"). It functions as the core root describing the quality of being firm or constant. - ly: A suffix of Germanic origin (Old English -līce), used to form adverbs from adjectives, indicating manner or way.