Tenuous means so thin or slight that it may not hold. A tenuous link, a tenuous grip, tenuous evidence.
It is nearly always about arguments and connections, where a tenuous link is one the speaker does not believe. The Latin means thin, and the physical sense survives in describing a tenuous atmosphere.
1adjectivetenuousSo thin or slight that it may not hold.
“His connection to the famous actress is tenuous: his cousin once met her at a party.”
tenuous is a quality.
Latin tenuis means thin or fine, from a root meaning to stretch.
Irregularly formed from tenuis + ous. Compare tenuious.
Etymology from Wiktionary, CC BY-SA