| APA | Smart Define. (2015). formidableness thesaurus. Retrieved September 24, 2026, from https://smartdefine.org/formidableness/thesaurus/synonyms |
| Chicago | Smart Define. 2015. "formidableness thesaurus" https://smartdefine.org/formidableness/thesaurus/synonyms (accessed September 24, 2026). |
| Harvard | Smart Define 2015, formidableness thesaurus, Smart Define, viewed 24 September, 2026, <https://smartdefine.org/formidableness/thesaurus/synonyms>. |
| MLA | Smart Define. "formidableness thesaurus" 14 April 2015. Web. 24 September 2026. <https://smartdefine.org/formidableness/thesaurus/synonyms> |