State head tackling socialist in charge (9)
I believe the answer is:
predicate
'state' is the definition.
(I've seen this before)
'head tackling socialist in charge' is the wordplay.
'head' becomes 'pate' (humorous term for the head).
'tackling' means one lot of letters goes inside another (to tackle is to take possession of).
'socialist' becomes 'red' (socialism is often associated with the colour red).
'in charge' becomes 'ic' (abbreviation for 'in charge').
'red'+'ic'='redic'
'pate' enclosing 'redic' is 'PREDICATE'.
(Other definitions for predicate that I've seen before include "Found" , "It says something about the subject in a sentence" , "Word in a sentence that make a statement about the subject" , "base" , "Assert, affirm" .)