Unvaluable

Part of speech: adjective

Definitions

1. An item regarded as lacking any value or usefulness in various scenarios
2. Something that possesses no significant worth or practical use
3. Describing an object or concept that holds zero meaningful value or benefit

Etymology: Adding "un-" to "valuable" produces "unvaluable," and the sense is plain: something with no worth at all. The more interesting relative is "invaluable." English already had that word, and it means the opposite of what one might expect. Something invaluable is so precious that it cannot be priced, so the word praises a thing rather than calling it worthless. The two words sit side by side in English as a pair of doublets, with "unvaluable" formed in English by attaching the prefix "un-" to "valuable." The suffix "-able" traces back through Old French and Latin, where it came from "-abilis," a form meaning "able to be" something, and "valuable" carries the idea of "able to be valued." Because "unvaluable" was built from familiar parts rather than borrowed, it is less common than "invaluable" and is often used where a writer wants to stress that something has been judged worthless. The two words therefore pull in opposite directions on the same root.