The adverb 'validly' is built upon the adjective 'valid', which originates from the Latin validus, meaning strong or powerful, itself derived from the verb valere (to be strong, be worth). The core semantic concept of strength and effectiveness evolved from physical power to logical soundness and legal authority. The adverbial suffix '-ly', of Germanic origin, was attached to this adjective to form a word describing the manner in which an action—such as an argument, claim, or procedure—is performed with soundness, legitimacy, or effectiveness.

Structure: valid (strong, sound) + ly (adverb suffix) - valid: From Latin validus (strong, powerful, effective), from valere (to be strong, be well). Serves as the adjectival root. - ly: From Old English -līc (having the form or character of), an adverbial suffix forming adverbs from adjectives.