The word 'tenuous' originates from the Latin adjective tenuis, meaning thin, fine, or slight. This Latin term is derived from the Proto-Indo-European root ten-, meaning "to stretch," which is the source of a wide array of English words related to thinness, tension, and extension, such as 'tendon,' 'tender,' and 'extend.' The literal sense of "thin" (as in a tenuous thread) evolved naturally into the figurative meaning of "weak, insubstantial" (as in a tenuous argument or connection). Thus, the modern abstract meaning of something being flimsy, weak, or having little strength is a direct metaphorical extension of the original physical concept of being stretched thin.

Structure: tenu (thin) + ous (adjective suffix) - tenu: From Latin tenuis, meaning thin, fine, slight. - ous: A suffix forming adjectives, from Latin -osus, meaning full of, characterized by.