strenuous

Adjective

strenuous (comparative more strenuous, superlative most strenuous)

1. Having great vigour or energy; forceful.
   • strenuous exercise
   • strenuous activity

   Synonyms:

   ardent, earnest, eager, energetic, determined, resolute, vigorous, zealous

2. Requiring great exertion; very laborious.
   • It [Troutbeck] has religious isolation also, for it is several miles—and very strenuous miles in winter—from the parish church at Mungrisdale, and the introduction of the harmonium to the waiting room was due to the zeal of a vicar of many years ago who, in the absence of any other room in the...1951 October, “Notes and News: The Harmonium at Troutbeck”, in Railway Magazine, page 709
   • We can achieve this god‐likeness only by unremitting and strenuous effort of the intellect.1961, J. A. Philip, “Mimesis in the Sophistês of Plato”, in Proceedings and Transactions of the American Philological Association 92, page 467