53 entries under adjective topic. ×

11
serious(expression, severity, earnest, harshness)
8
earnest(noun, expression, cool, cold)
8
grave(expression, severity, earnest, harshness)
7
important(importance, significance, consequence, eminence)
6
heavy(severity, earnest, harshness)
6
significant(importance, significance, consequence, eminence)
6
sophisticated(severity, sophistication, harshness, grievousness)
6
thoughtful(happy, careless, sober, superficial)
5
austere(hard, severe, harsh, stern)
5
severe(expression, hard, harsh, severity)
4
hard(severe, harsh, severity, stern)
4
unimpassioned(upset, light, happy, sober)
3
sober(upset, light, frivolous, disciplined)
2
weighty(severity, sophistication, harshness, grievousness)
2
heartrending(severity, sophistication, harshness, grievousness)
2
burdensome(severity, sophistication, harshness, grievousness)
2
critical(expression, severity, earnest, harshness)
2
grievous(severity, sophistication, harshness, grievousness)
2
profound(importance, significance, consequence, eminence)
2
rigid(hard, severe, harsh, stern)
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APASmart Define. (2015). unserious thesaurus. Retrieved September 29, 2026, from https://smartdefine.org/unserious/thesaurus/antonyms
ChicagoSmart Define. 2015. "unserious thesaurus" https://smartdefine.org/unserious/thesaurus/antonyms (accessed September 29, 2026).
HarvardSmart Define 2015, unserious thesaurus, Smart Define, viewed 29 September, 2026, <https://smartdefine.org/unserious/thesaurus/antonyms>.
MLASmart Define. "unserious thesaurus" 10 April 2015. Web. 29 September 2026. <https://smartdefine.org/unserious/thesaurus/antonyms>