This means of escape is decidedly eccentric (3,3)
I believe the answer is:
way out
'eccentric' is the definition.
(I've seen this before)
'this means of escape is decidedly' is the wordplay.
I cannot really see how this works, but
'means' could be 'way' (synonyms) and 'way' is found in the answer.
'of' could be 'o' and 'o' is present in the answer.
The remaining letters 'ut' is a valid word which might be clued in a way I don't understand.
This may be the basis of clue (or it may be nonsense).
Can you help me to learn more?
(Other definitions for way out that I've seen before include "Exit - weird" , "Exit - eccentric" , "Unconventional - exit" , "Hit wicket, for example" , "Rather unusual" .)