85 entries under reflective topic. ×

93
grave(adjective, calm, dull, quiet, help)
43
weighty(adjective, good, dull, hard, great)
37
earnest(noun, adjective, calm, dull, work)
30
sober(adjective, calm, dull, quiet, cool)
30
difficult(adjective, hard, tough, easy, harsh)
26
profound(adjective, hard, difficult, complex, deep)
19
heavy(adjective, strong, hard, great, tough)
11
deep(adjective, keen, important, significant, thoughtful)
11
thoughtful(adjective, severe, deep, sober, thinking)
8
intent(adjective, firm, determined, thoughtful, sober)
8
ruminative(adjective, reasonable, rational, thoughtful, sober)
7
pensive(adjective, set, keen, unhappy, gloomy)
4
contemplative(adjective, reasonable, thoughtful, sober, thinking)
4
meditative(adjective, set, thoughtful, thinking, stern)
3
careful(adjective, regular, thoughtful, practical, competent)
3
cogitative(adjective, reasonable, keen, deep, thoughtful)
3
musing(adjective, reasonable, keen, deep, thoughtful)
3
reasonable(adjective, calm, keen, sensible, restrained)
3
wistful(adjective, reasonable, keen, unhappy, gloomy)
2
abstruse(intense, heavy, deep, fierce, thoughtful)
10 years ago|45k views|share |citing 
APASmart Define. (2016). serious thesaurus. Retrieved September 24, 2026, from https://smartdefine.org/serious/thesaurus/synonyms
ChicagoSmart Define. 2016. "serious thesaurus" https://smartdefine.org/serious/thesaurus/synonyms (accessed September 24, 2026).
HarvardSmart Define 2016, serious thesaurus, Smart Define, viewed 24 September, 2026, <https://smartdefine.org/serious/thesaurus/synonyms>.
MLASmart Define. "serious thesaurus" 24 February 2016. Web. 24 September 2026. <https://smartdefine.org/serious/thesaurus/synonyms>