- elusive - difficult to describe; "a haunting elusive odor"
Antonym: identifiable (indirect, via unidentifiable)
- elusive, evasive - skillful at eluding capture; "a cabal of conspirators, each more elusive than the archterrorist"- David Kline
Antonym: artless (indirect, via artful)
- elusive, subtle - be difficult to detect or grasp by the mind; "his whole attitude had undergone a subtle change"; "a subtle difference"; "that elusive thing the soul"
Antonyms: palpable, tangible (indirect, via impalpable)