fatuous

the word 'fatuous' has a direct lineage from the latin adjective 'fatuus', which meant foolish, silly, or insipid. this latin root itself is of obscure origin, though some scholars suggest a possible connection to notions of being struck or amazed, leading to a state of stupor. entering english in the early 17th century, it retained the core sense of vacuous foolishness. the suffix '-ous', borrowed from latin, routinely forms adjectives meaning 'possessing the qualities of', thus constructing a word that literally means 'characterized by foolishness'.

Structure: fatu (foolish) + ous (adjective suffix) fatu is from latin 'fatuus' (foolish, silly). ous is an english adjective-forming suffix from latin '-osus' (full of, characterized by).