"Stamina" Natural Recordings by Native Speakers
The term "stamina" refers to the physical or mental endurance needed to sustain or withstand a long-lasting and often demanding activity, effort, or situation. It encompasses the capacity for continued performance despite challenges, weariness, or hardship.
Stalwarts are individuals who are strong and established, often in a particular profession or activity. They are respected and admired for their skills, experience, and dedication.
I couldn't find any definition for the word "stamened". It is possible that it is a misspelling or a non-standard word.