Tough love, including current arrangement of locks (6)
I believe the answer is:
'arrangement of locks' is the definition.
(I've seen this before)
'tough love including current' is the wordplay.
'tough' becomes 'hard' ('hard' is associated in meaning with 'tough'**).
'love' becomes 'o' (In tennis, 'love' means 'zero').
'including' means one lot of letters goes inside another.
'current' becomes 'i' (symbol for electric current).
'hardo' going around 'i' is 'HAIRDO'.
(Other definitions for hairdo that I've seen before include "Arrangement of locks" , "Eg, beehive or mullet" , "What one may have expected from 'Sweeney Todd'" , "Style for one's crowning glory" , "Say, crew cut" .)