1
unclear(incoherent, unfathomable, incomprehensible, impenetrable, opaque)
1
uncomprehensible(adjective, incomprehensible)
1
unimaginable(adjective, unfathomable, impenetrable, opaque, unintelligible)
1
unknowable(incoherent, unfathomable, incomprehensible, impenetrable, opaque)
0
after(low-set, low-lying)
0
back of(expression, low-set, low-lying)
0
baseless
0
bathycolpian
0
below(low-set, low-lying)
0
benthal
0
benthopelagic
0
bottommost(low-set, low-lying, subjacent)
0
buried
0
depth
0
endless
0
eternal
0
extending deeply(expression, adjective, bottomless)
0
fathom
0
ground-level(low-set, low-lying, subjacent)
0
hard to understand(expression, idiom)
11 years ago|2.1k views|share |citing 
APASmart Define. (2015). fathomless thesaurus. Retrieved September 21, 2026, from https://smartdefine.org/fathomless/thesaurus/synonyms
ChicagoSmart Define. 2015. "fathomless thesaurus" https://smartdefine.org/fathomless/thesaurus/synonyms (accessed September 21, 2026).
HarvardSmart Define 2015, fathomless thesaurus, Smart Define, viewed 21 September, 2026, <https://smartdefine.org/fathomless/thesaurus/synonyms>.
MLASmart Define. "fathomless thesaurus" 10 April 2015. Web. 21 September 2026. <https://smartdefine.org/fathomless/thesaurus/synonyms>