1. difficult to describe

- a haunting elusive odor

Similar word(s): unidentifiable

2. skillful at eluding capture

- a cabal of conspirators, each more elusive than the archterrorist

Similar word(s): artful

3. difficult to detect or grasp by the mind or analyze

- that elusive thing the soul

Similar word(s): impalpable, subtle

4. making great mental demands; hard to comprehend or solve or believe

Similar word(s): difficult, hard, baffling, knotty, problematic, problematical, tough

Sentences with elusive as an adjective:

- The elusive criminal was arrested

- A precise definition of diarrhea is elusive (Robbin's pathology, 8th ed)