918 entries under adjective topic. ×

19
disturbing(hard, difficult, complex)
19
esoteric(hard, difficult, complex)
19
grinding(hard, difficult, harsh, cruel)
19
hard-nosed(strong, hard, tough, severe)
19
heavy(strong, hard, great, tough)
19
intricate(hard, difficult, complex, awkward)
19
knotty(hard, difficult, complex, awkward)
19
ponderous(hard, difficult, complex)
19
rough(bad, strong, hard, tough)
19
rugged(strong, hard, tough, difficult)
19
sensitive(hard, difficult, complex)
19
sophisticated(hard, difficult, complex)
19
sticky(hard, difficult, complex, awkward)
19
toilful(hard, difficult, complex, awkward)
19
toilsome(hard, difficult, harsh, cruel)
19
vital(great, severe, importance, big)
18
hefty(hard, difficult, complex)
18
messy(hard, difficult, unpleasant, complex)
18
taxing(hard, difficult, complex)
18
tricky(hard, difficult, complex, awkward)
10 years ago|45k views|share |citing 
APASmart Define. (2016). serious thesaurus. Retrieved September 26, 2026, from https://smartdefine.org/serious/thesaurus/synonyms
ChicagoSmart Define. 2016. "serious thesaurus" https://smartdefine.org/serious/thesaurus/synonyms (accessed September 26, 2026).
HarvardSmart Define 2016, serious thesaurus, Smart Define, viewed 26 September, 2026, <https://smartdefine.org/serious/thesaurus/synonyms>.
MLASmart Define. "serious thesaurus" 24 February 2016. Web. 26 September 2026. <https://smartdefine.org/serious/thesaurus/synonyms>