Work during holiday leading to a disturbance (4-2)
I believe the answer is:
hoop-la
'disturbance' is the definition.
'work during holiday leading to a' is the wordplay.
'work' becomes 'op' (abbreviation for opus**).
'during' is an insertion indicator.
'holiday' becomes 'hol' (short for holiday).
'leading to' means one lot of letters go next to another (some letters go before or lead others).
'op' inserted inside 'hol' is 'hoopl'.
'hoopl'+'a'='HOOP-LA'
(Other definitions for hoop-la that I've seen before include "Throwing fairground game" , "Game in which rings are thrown over objects in order to win them" .)