Unearth source of real acerbity in political party (6,2)
I believe the answer is:
dredge up
'unearth' is the definition.
(I've seen this in another clue)
'source of real acerbity in political party' is the wordplay.
'source of' indicates taking the first letters (the start - or source - of the word).
'acerbity' becomes 'edge' (I can't justify this - if you can you should believe this answer much more).
'in' means one lot of letters goes inside another.
'political party' becomes 'DUP' (Democratic Unionist Party).
The initial letter of 'real' is 'r'.
'r'+'edge'='redge'
'redge' going into 'dup' is 'DREDGE UP'.
Can you help me to learn more?
(Other definitions for dredge up that I've seen before include "Bring (something unwelcome) to the attention" , "Reluctantly recall" , "Bring (something unwelcome) to light" , "raise from bed?" , "Bring (something best forgotten) to light" .)