Broadcaster is keen to employ star (8)
I believe the answer is:
asterisk
'star' is the definition.
(synonyms)
'broadcaster is keen to employ' is the wordplay.
'to employ' indicates the answer is hidden within the clue (the answer's letters are employed by the clue).
'ASTERISK' can be found hidden inside 'broadcaster is keen'.
(Other definitions for asterisk that I've seen before include "Star-shaped character used in printing" , "Star in print" , "Star on a page" , "Star for the printer" , "Printer's star" .)