Northern Irish politicians securing money repository (4)
I believe the answer is:
dump
'repository' is the definition.
(thesaurus)
'northern irish politicians securing money' is the wordplay.
'northern irish politicians' becomes 'dup' (Democratic Unionist Party).
'securing' indicates putting letters inside.
'money' becomes 'm' (abbreviation in economics).
'dup' enclosing 'm' is 'DUMP'.
(Other definitions for dump that I've seen before include "Rubbishy place" , "Disposal site" , "Public rubbish tip" , "Place where rubbish is deposited" , "Unload" .)