51 entries under expression topic. ×

28
closed book(noun, idiom, trouble, challenge)
8
mystery story(noun, idiom, question, secret)
6
tough nut to crack(noun, question, secret, puzzle)
6
crossword puzzle(noun, idiom, difficult, issue)
6
fair question(noun, idiom, question, secret)
5
bone of contention(noun, idiom, question, secret)
5
crux criticorum(noun, idiom, secret, brain)
5
field of inquiry(noun, idiom, question, secret)
5
knotty point(noun, idiom, question, secret)
5
matter in dispute(noun, idiom, question, secret)
5
moot point(noun, idiom, question, secret)
4
brain twister(noun, idiom, difficult, issue)
4
vexed question(noun, idiom, trouble, challenge)
4
diagnus vindice nodus(noun, idiom, problem, secret)
4
jigsaw puzzle(idiom, secret, mystery, brain-twister)
4
open question(noun, idiom, question, secret)
4
plain question(noun, idiom, question, secret)
4
point in dispute(noun, idiom, question, secret)
4
question at issue(noun, idiom, question, secret)
4
sealed book(noun, idiom, problem, secret)
<123>
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APASmart Define. (2016). enigma thesaurus. Retrieved September 20, 2026, from https://smartdefine.org/enigma/thesaurus/synonyms
ChicagoSmart Define. 2016. "enigma thesaurus" https://smartdefine.org/enigma/thesaurus/synonyms (accessed September 20, 2026).
HarvardSmart Define 2016, enigma thesaurus, Smart Define, viewed 20 September, 2026, <https://smartdefine.org/enigma/thesaurus/synonyms>.
MLASmart Define. "enigma thesaurus" 1 April 2016. Web. 20 September 2026. <https://smartdefine.org/enigma/thesaurus/synonyms>