Shout at graduate redneck extremist (4)
I believe the answer is:
bark
'shout' is the definition.
(thesaurus)
'at graduate redneck extremist' is the wordplay.
'at' says to put letters next to each other.
'graduate' becomes 'ba' (someone with a Bachelor of Arts degree).
'extremist' says to hollow out the word (remove centre letters) (I've seen 'extremists' mean this).
'redneck' with its centre removed is 'rk'.
'ba' next to 'rk' is 'BARK'.
(Other definitions for bark that I've seen before include "Cri de cur?" , "Dog sound or tree coating" , "Dogs might react to this part of a tree" , "Tree trunk's outer layer" , "Skin of tree" .)