tenuousyoudaoicibaDictYouDict
tenuous: [16] Tenuous comes from the same ultimate ancestor as thin. It is an alteration of an earlier and now defunct tenuious, which was adapted from Latin tenuis ‘thin’. And this went back to the Indo-European base *ten- ‘stretch’, a variant of which produced English thin.
=> tend, thin
tenuous (adj.)youdaoicibaDictYouDict
1590s, "thin, unsubstantial," irregularly formed from Latin tenuis "thin, drawn out, meager, slim, slender," figuratively "trifling, insignificant, poor, low in rank," from PIE root *ten- "to stretch" (cognates: Sanskrit tanuh "thin," literally "stretched out;" see tenet) + -ous. The correct form with respect to the Latin is tenuious. The figurative sense of "having slight importance, not substantial" is found from 1817 in English. Related: Tenuously; tenuousness.