Longman Dictionary of Contemporary English - elusive

~ adj 1 an elusive person or animal is difficult to find or not often seen  (an elusive man who was never in his office) 2 an elusive result is difficult to achieve  (Success in the business world has so far proved elusive.) 3 an elusive idea or quality is difficult to describe or understand  (The meaning of the poem was somewhat elusive.) - elusively adv - elusiveness n