Here's how it breaks down:
* Tenuous: Comes from the Latin "tenuis" directly and refers to something thin, weak, or lacking in substance.
* Attenuate: Comes from the Latin "attenuare," meaning "to make thin."
Both words retain the core meaning of "thinness" from their shared root, but each word has evolved slightly in its usage. "Tenuous" is often used to describe something fragile or weak, while "attenuate" implies a process of thinning or weakening.