3
bootleg(adjective, illegal)
3
illegal
3
unlawful
2
clandestine(adjective, secret, sly)
2
furtive(hidden, fraudulent)
2
illegitimate(hidden, sly, illegal, fraudulent, illicit)
2
illicit(hidden, sly, illegal, fraudulent, illegitimate)
2
sly
2
sneaky(sly, fraudulent)
2
undercover(sly, fraudulent)
2
underground(hidden, fraudulent)
1
actionable
1
against the law(expression, idiom)
1
anarchic
1
anarchistic
1
artful(hidden, sly, fraudulent)
1
back door
1
backstairs
1
black market
1
cloak-and-dagger(hidden, sly, fraudulent)
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APASmart Define. (2015). under-the-counter thesaurus. Retrieved September 20, 2026, from https://smartdefine.org/under-the-counter/thesaurus/synonyms
ChicagoSmart Define. 2015. "under-the-counter thesaurus" https://smartdefine.org/under-the-counter/thesaurus/synonyms (accessed September 20, 2026).
HarvardSmart Define 2015, under-the-counter thesaurus, Smart Define, viewed 20 September, 2026, <https://smartdefine.org/under-the-counter/thesaurus/synonyms>.
MLASmart Define. "under-the-counter thesaurus" 13 April 2015. Web. 20 September 2026. <https://smartdefine.org/under-the-counter/thesaurus/synonyms>