Initially bitter beer causes misery (4)
I believe the answer is:
bale
'misery' is the definition.
(thesaurus)
'initially bitter beer' is the wordplay.
'initially' indicates taking the first letters.
'beer' becomes 'ale' (I've seen this before).
The first letter of 'bitter' is 'b'.
'b'+'ale'='BALE'
'causes' acts as a link.
(Other definitions for bale that I've seen before include "Large bundle as of straw" , "(Make into a) bundle of hay" , "Bound bundle" , "Parcel" , "Evil - bundle" .)