Keen to get away (3)
I believe the answer is:
out
'away' is the definition.
(synonyms)
I don't understand how the remainder of the clue works.
Can you help me to learn more?
(Other definitions for out that I've seen before include "Means of escape" , "Known" , "Mistaken; unconscious" , "In error" , "Walking back to the pavilion" .)