Physical coming-together? Duke is accepting restraint on movement (10)
I believe the answer is:
fisticuffs
'physical coming-together?' is the definition.
(fisticuffs means a fight or confrontation)
'duke is accepting restraint on movement' is the wordplay.
'duke' becomes 'fist' (put up your dukes).
'accepting' indicates putting letters inside (inserted letters are accepted).
'restraint on movement' becomes 'cuff' (eg handcuffs).
'is' enclosing 'cuff' is 'icuffs'.
'fist'+'icuffs'='FISTICUFFS'
(Other definitions for fisticuffs that I've seen before include "Pugilism" , "Fighting with punches" , "Scrap" , "Bare-knuckle combat" , "Hand-to-hand combat?" .)