2
under cover(expression, obscure, dark, unseen)
2
under wraps(expression, clandestine, underground, undisclosed)
2
undercover(secret, hidden, clandestine, underground, concealed)
2
underground(obscure, secret, hidden, concealed, unseen)
2
undetermined(adjective, rough, strange, new, determined)
2
unfathomable(obscure, dark, superior, strange, mysterious)
2
unhonored
2
unmapped
2
unmarked
2
unnoticeable
2
unprecedented(adjective, obscure, unusual, strange, new)
2
unpublished(obscure, clandestine, underground, undisclosed, unrevealed)
2
untouched(adjective, unusual, strange, fresh, original)
2
weird(adjective, obscure, strange, deep, mysterious)
1
indistinct(adjective, rough, vague, general, unclear)
1
able
1
abnormal(adjective, obscure, dark, superior, mysterious)
1
adopted(experience, distant, different, unfamiliar, external)
1
advanced(adjective, unusual, strange, fresh, original)
1
afterlife
11 years ago|26k views|share |citing 
APASmart Define. (2015). unknown thesaurus. Retrieved September 22, 2026, from https://smartdefine.org/unknown/thesaurus/synonyms
ChicagoSmart Define. 2015. "unknown thesaurus" https://smartdefine.org/unknown/thesaurus/synonyms (accessed September 22, 2026).
HarvardSmart Define 2015, unknown thesaurus, Smart Define, viewed 22 September, 2026, <https://smartdefine.org/unknown/thesaurus/synonyms>.
MLASmart Define. "unknown thesaurus" 10 April 2015. Web. 22 September 2026. <https://smartdefine.org/unknown/thesaurus/synonyms>