Leader of orchestra regularly broke wind (4)
I believe the answer is:
oboe
'wind' is the definition.
(oboe is a kind of wind)
'leader of orchestra regularly broke' is the wordplay.
'leader of' says to take the initial letters.
'regularly' means one should take alternating letters (regularly take one letter, leave next etc.).
The initial letter of 'orchestra' is 'o'.
The alternating letters of 'broke' are 'boe'.
'o'+'boe'='OBOE'
(Other definitions for oboe that I've seen before include "Slender double-reed instrument" , "Producer of notes" , "blow it!" , "Cor anglais in its family" , "Double-reed woodwind" .)