vigor
n. uncountable C1 Advanced US //ˈvɪɡɝ// vig·or
n. physical or mental strength and energy. You use this to describe someone who works or acts with a lot of power and focus.
n. physical strength and good health; the capacity for survival or continued growth in a biological or social context. Often associated with robustness and active force.
She started her new job with great vigor.
The plants grew with surprising vigor after the gardener added the new fertilizer to the soil.
The committee debated the proposed reforms with renewed vigor, determined to reach a consensus before the legislative session concluded at the end of the month.
Usage
Commonly follows the preposition 'with'. In British English, the word is spelled 'vigour'.