| APA | Smart Define. (2013). slap the forehead thesaurus. Retrieved September 25, 2026, from https://smartdefine.org/slap_the_forehead/thesaurus/synonyms |
| Chicago | Smart Define. 2013. "slap the forehead thesaurus" https://smartdefine.org/slap_the_forehead/thesaurus/synonyms (accessed September 25, 2026). |
| Harvard | Smart Define 2013, slap the forehead thesaurus, Smart Define, viewed 25 September, 2026, <https://smartdefine.org/slap_the_forehead/thesaurus/synonyms>. |
| MLA | Smart Define. "slap the forehead thesaurus" 18 May 2013. Web. 25 September 2026. <https://smartdefine.org/slap_the_forehead/thesaurus/synonyms> |