100 entries under restrained topic. ×

1
down-to-earth(adjective, calm, tough, plain)
1
hard-boiled(adjective, calm, strong, hard, tough)
1
inhibited(adjective, calm, sensible, dark)
1
levelheaded(adjective, calm, reasonable, sensible, dark)
1
low-key(adjective, calm, quiet, gentle, sensible)
1
plain(adjective, calm, open, tough, honest)
1
repressed(adjective, calm, quiet, gentle, relaxed)
1
soft(adjective, calm, quiet, gentle, sensible)
1
toned down(expression, adjective, calm, quiet, gentle)
1
unexcited(adjective, calm, sensible, dark)
1
unimpassioned(adjective, calm, tough, dark)
0
abnegating(adjective, calm, sensible, dark)
0
callous(adjective, calm, subdued, impassive)
0
casual(adjective, calm, subdued, impassive)
0
cold fish(expression, adjective, calm, subdued)
0
constrained(adjective, calm, sensible, dark)
0
domestic(quiet, gentle)
0
domesticated(adjective, quiet, gentle, sober)
0
down in the mouth(expression, idiom, quiet, gentle)
0
easy-going(adjective, calm, subdued, impassive)
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APASmart Define. (2016). serious thesaurus. Retrieved September 27, 2026, from https://smartdefine.org/serious/thesaurus/synonyms
ChicagoSmart Define. 2016. "serious thesaurus" https://smartdefine.org/serious/thesaurus/synonyms (accessed September 27, 2026).
HarvardSmart Define 2016, serious thesaurus, Smart Define, viewed 27 September, 2026, <https://smartdefine.org/serious/thesaurus/synonyms>.
MLASmart Define. "serious thesaurus" 24 February 2016. Web. 27 September 2026. <https://smartdefine.org/serious/thesaurus/synonyms>