stren-u-ous / strĕn-yo͞o-əs
1. requiring a great deal of effort, exertion or endurance
I wish to preach, not the doctrine of ignoble ease, but the doctrine of the strenuous life.
Theodore Roosevelt, 1858 – 1919
2. energetic, active, zealous
Let your hearts be filled with the strenuous desire that tranquillity and harmony may encircle all this warring world.
Abdu’l-Bahá, 1844 – 1921