Protest Hoskins making comeback in work (4)
I believe the answer is:
demo
'protest' is the definition.
(demonstration)
'hoskins making comeback in work' is the wordplay.
'hoskins' becomes 'me' (where the crossword setter is 'Hoskins').
'making comeback' is a reversal indicator.
'in' is an insertion indicator.
'work' becomes 'do' (synonyms).
'me' backwards is 'em'.
'em' placed inside 'do' is 'DEMO'.
(Other definitions for demo that I've seen before include "Tape sent to recording studio" , "Political protest" , "presentation" , "Eg, protest march" , "illustration" .)