Meaning of tenuous

ten•u•ous

1. thin or slender in form, as a thread.
2. lacking a sound basis, as reasoning; unsubstantiated; weak: a tenuous argument.
3. thin in consistency; rare or rarefied.
4. of slight importance or significance; unsubstantial: He holds a rather tenuous position in history.
5. lacking in clarity; vague: He gave a rather tenuous account of his past life.