untenuous
/ʌnˈtɛnʃəs, -ˈtɛnjuəs/Definitions
1. adjective
Lacking in or not having tenacity or firmness; feeble or weak.
“Her untenuous resolve crumbled under the pressure.”
2. noun
A person or thing that lacks tenacity or firmness.
“The team’s untenuous member was the first to give up during the marathon.”