Formidable
Formidable adjective - Requiring considerable physical or mental effort.
Usage example: running a marathon is a formidable undertaking
Stiff is a synonym for formidable in onerous topic. In some cases you can use "Stiff" instead an adjective "Formidable".
Nearby Word: formidably
Stiff
Stiff adjective - Requiring considerable physical or mental effort.
Usage example: we'll have a stiff climb to actually reach the summit
Formidable is a synonym for stiff in difficult topic. Sometimes you can use "Formidable" instead an adjective "Stiff".
Mutual synonyms
Cite this Source
Stiff and Formidable. (2016). Retrieved 2026, August 15, from https://thesaurus.plus/related/formidable/stiff
Formidable & Stiff. N.p., 2016. Web. 15 Aug. 2026. <https://thesaurus.plus/related/formidable/stiff>.
Stiff or Formidable. 2016. Accessed August 15, 2026. https://thesaurus.plus/related/formidable/stiff.
Google Ngram Viewer shows how "formidable" and "stiff" have occurred on timeline