Dove, flying among trees, agitated docker (9)
I believe the answer is:
stevedore
'docker' is the definition.
(synonyms)
'dove flying among trees agitated' is the wordplay.
'flying' indicates an anagram (letters fly around into new positions).
'among' is an insertion indicator (inserted letters are placed among others).
'agitated' is an anagram indicator.
'dove' with letters rearranged gives 'vedo'.
'trees' with letters rearranged gives 'stere'.
'vedo' placed into 'stere' is 'STEVEDORE'.
(Other definitions for stevedore that I've seen before include "Hold worker" , "dock pay for him?" , "One loads and unloads ships" , "Dock-worker loads and unloads ships" , "Dock worker" .)