abstruse
I
adjective
abstract, ambiguous, attenuated, cloudy, complex, difficult to understand, elusive, enigmatic, esoteric, hidden, incomprehensible, indefinable, indefinite, inexplicable, mysterious, nebulous, obscure, profound, puzzling, rarefied, recondite, remote, subtle, technical, unclear, unfathomable, vague
II
index
ambiguous, complex, elusive, esoteric, hidden, inapprehensible, incomprehensible, indefinable, inexplicable, mysterious, nebulous, private (confidential), profound (esoteric), recondite, secret, technical
Burton's Legal Thesaurus.
William C. Burton.
2006