Idiot Everyman's anger about fence regularly ignored (8)
I believe the answer is:
imbecile
'idiot' is the definition.
(I know that idiot can be written as imbecile)
'everyman's anger about fence regularly ignored' is the wordplay.
'everyman's' becomes 'I'm' (where the setter is Everyman).
'anger' becomes 'bile' (I've seen this in another clue).
'about' is an insertion indicator.
'regularly ignored' means one should take alternating letters (letters removed at regular intervals).
The alternate letters of 'fence' are 'ec'.
'bile' enclosing 'ec' is 'becile'.
'im'+'becile'='IMBECILE'
(Other definitions for imbecile that I've seen before include "Charlie" , "Moron or cretin" , "Jerk" , "An unintelligent person, very low IQ" , "Abusive word for foolish person" .)