Discard diamonds with irritation (5)
I believe the answer is:
ditch
'discard' is the definition.
(thesaurus)
'diamonds with irritation' is the wordplay.
'diamonds' becomes 'd' (abbreviation in bridge say).
'with' means one lot of letters go next to another.
'irritation' becomes 'itch' (I've seen this before).
'd'+'itch'='DITCH'
(Other definitions for ditch that I've seen before include "Type of trench" , "Gully or furrow" , "Abandon; one dug" , "side of field?" , "Narrow channel" .)