giving careful attention to detail; hard to please; excessively concerned with cleanliness; "a fastidious and incisive intellect"; "fastidious about personal cleanliness"
having complicated nutritional requirements; especially growing only in special artificial cultures; "fastidious microorganisms"; "certain highly specialized xerophytes are extremely exacting in their requirements"
difficult to penetrate; incomprehensible to one of ordinary understanding or knowledge; "the professor's lectures were so abstruse that students tended to avoid them"; "a deep metaphysical theory"; "some recondite problem in historiography"