Those opposed to sacking current social workers (4)
I believe the answer is:
ants
'social workers' is the definition.
(I've seen this in another clue)
'those opposed to sacking current' is the wordplay.
'those opposed' becomes 'antis' (I've seen this in another clue).
'to sacking' indicates named letters should be taken away.
'current' becomes 'I' (symbol for electric current).
'antis' with 'i' taken out is 'ANTS'.
(Other definitions for ants that I've seen before include "Soldiers" , "Emmets" , "Small social insects" , "Hard workers" , "24 [INSECT] s" .)