4 Answers

Elusive is, as stated by Lav and Benthere, something that is hard to grasp, capture, understand, obtain.
On my ankle I have a tattoo of a butterfly.  The body of the butterfly is the Chinese word for "happiness".  A butterfly is elusive......hard to obtain.  Sometimes, happiness can be as elusive as a butterfly.

Bob, Lav and Bob have already said so well what elusive means. Simply something that is difficult to grasp tending to escape or dissapear or difficult to capture. Difficult to remember or understand.

Therefore something eludes us either physically or mentally.  

Bob, Lav and Bob have already said so well what elusive means. Simply something that is difficult to grasp tending to escape or dissapear or difficult to capture. Difficult to remember or understand.

Therefore something eludes us either physically or mentally.  

Elusive is an adjective, meaning hard to catch or difficult to understand.

Example:
Even the experienced, old fisherman admitted that the trout in the river were quite elusive.

Ive found that from (http://www.english-test.net/gmat/vocabulary/meanings/093/gmat-words.php#elusive). Hope it could help, though i think its quite late.