Some crocodiles, when disturbed, can be harmless (6)
I believe the answer is:
docile
'harmless' is the definition.
Both the definition and answer are adjectives. Maybe you can see an association between them that I don't see?
'some crocodiles when disturbed can' is the wordplay.
'some' indicates the central letters.
'when disturbed' is an anagram indicator.
'can' becomes 'le' (I am not sure about this - if you are sure you should give a lot more credence to this answer).
The central letters of 'crocodiles' are 'codi'.
'codi' with letters rearranged gives 'doci'.
'doci'+'le'='DOCILE'
'be' acts as a link.
Can you help me to learn more?
(Other definitions for docile that I've seen before include "Easily handled or managed" , "Gentle, tame" , "easy to manage" , "Meek and biddable" , "Gentle and pliant" .)