Old boozer regularly produces wind (4)
I believe the answer is:
oboe
'wind' is the definition.
(oboe is a kind of wind)
'old boozer regularly' is the wordplay.
'old' becomes 'o' (common abbreviation eg in OE for Old English).
'regularly' indicates alternate letters (regularly take one letter, leave next etc.).
The alternating letters of 'boozer' are 'boe'.
'o'+'boe'='OBOE'
'produces' acts as a link.
(Other definitions for oboe that I've seen before include "Cor anglais in its family" , "Double-reed wind instrument" , "Source of music" , "it's blown" , "Instrument used in 1d" .)