Formidable
Formidable adjective - Requiring considerable physical or mental effort.
Usage example: running a marathon is a formidable undertaking
Opaque and formidable are semantically related. In some cases you can use "Opaque" instead an adjective "Formidable".
Nearby Word: formidably
Opaque
Opaque adjective - Having an often intentionally veiled or uncertain meaning.
Formidable and opaque are semantically related. Sometimes you can use "Formidable" instead an adjective "Opaque".
Nearby Words: opaqueness, opaquely
Cite this Source
Opaque and Formidable. (2016). Retrieved 2026, July 21, from https://thesaurus.plus/related/formidable/opaque
Formidable & Opaque. N.p., 2016. Web. 21 Jul. 2026. <https://thesaurus.plus/related/formidable/opaque>.
Opaque or Formidable. 2016. Accessed July 21, 2026. https://thesaurus.plus/related/formidable/opaque.
Google Ngram Viewer shows how "formidable" and "opaque" have occurred on timeline