| APA | Smart Define. (2013). grim faced thesaurus. Retrieved September 29, 2026, from https://smartdefine.org/grim_faced/thesaurus/synonyms |
| Chicago | Smart Define. 2013. "grim faced thesaurus" https://smartdefine.org/grim_faced/thesaurus/synonyms (accessed September 29, 2026). |
| Harvard | Smart Define 2013, grim faced thesaurus, Smart Define, viewed 29 September, 2026, <https://smartdefine.org/grim_faced/thesaurus/synonyms>. |
| MLA | Smart Define. "grim faced thesaurus" 18 May 2013. Web. 29 September 2026. <https://smartdefine.org/grim_faced/thesaurus/synonyms> |