Adjustment is required to circumvent many a dispute (11)
I believe the answer is:
altercation
'a dispute' is the definition.
(altercation is a kind of dispute)
'adjustment is required to circumvent many' is the wordplay.
'adjustment' becomes 'alteration' ('alteration' can be a synonym of 'adjustment').
'is required to circumvent' means one lot of letters goes inside another.
'many' becomes 'c' (C is the Roman numeral for 100).
'alteration' going around 'c' is 'ALTERCATION'.
(Other definitions for altercation that I've seen before include "Noisy argument" , "Squabble" , "Noisy disagreement" , "Noisy quarrel" , "heated argument" .)