Acting in clip to hide programme’s finale (7)
I believe the answer is:
interim
'acting' is the definition.
(synonyms)
'in clip to hide programme's finale' is the wordplay.
'clip' becomes 'trim' (synonyms).
'to hide' indicates putting letters inside.
'finale' indicates one should take the final letters.
The final letter of 'programme' is 'e'.
'trim' going around 'e' is 'terim'.
'in'+'terim'='INTERIM'
(Other definitions for interim that I've seen before include "temporary period" , "Meantime - provisional" , "Meantime; temporary" , "Stopgap" , "acting" .)