Unhappy waiting around, I dropped hamper (6)
I believe the answer is:
saddle
'hamper' is the definition.
(thesaurus)
'unhappy waiting around i dropped' is the wordplay.
'unhappy' becomes 'sad' (similar in meaning).
'waiting around' becomes 'idle' (I've seen this in another clue).
'dropped' is a deletion indicator.
'idle' with 'i' removed is 'dle'.
'sad'+'dle'='SADDLE'
(Other definitions for saddle that I've seen before include "Equestrian equipment" , "Lamb joint" , "Encumber" , "Jockey's seat" , "Cut of meat" .)