Disagree about line taken by Wood (5)
I believe the answer is:
clash
'disagree' is the definition.
(I know that clash is a more specific form of the action disagree)
'about line taken by wood' is the wordplay.
'about' becomes 'c' (circa).
'line' becomes 'l' (used when specifying particular lines from a poem).
'taken by' is a charade indicator (letters next to each other).
'wood' becomes 'ash' (wood from an ash tree).
'c'+'l'+'ash'='CLASH'
(Other definitions for clash that I've seen before include "Conflict, between colours say" , "Come into violent conflict" , "Collision (of colour)" , "Punk group; disagree" , "Conflict; be incompatible" .)