elusive
adjective /ɪˈluːsɪv/
  /ɪˈluːsɪv/
 - difficult to find, define or achieve- Eric, as elusive as ever, was nowhere to be found.
- the elusive concept of ‘literature’
- A solution to the problem of toxic waste is proving elusive.
 Extra ExamplesTopics Difficulty and failurec1- Further movie roles have proved somewhat elusive for the young actor.
- He was searching for the ever elusive ‘perfect job’.
- Sleep was strangely elusive.
- The murderer remained frustratingly elusive.
- Truth is a notoriously elusive quality.
 Oxford Collocations Dictionaryverbs- be
- prove
- become
- …
 - extremely
- fairly
- very
- …
 Word Originearly 18th cent.: from Latin elus- ‘eluded’ (from the verb eludere) + -ive.