Lively day with broadcaster (6)
I believe the answer is:
frisky
'lively' is the definition.
(I've seen this before)
'day with broadcaster' is the wordplay.
'day' becomes 'fri' (abbreviation for Friday).
'with' is a charade indicator (letters next to each other).
'broadcaster' becomes 'sky' (Sky is a broadcast TV channel).
'fri'+'sky'='FRISKY'
(Other definitions for frisky that I've seen before include "Lively like playful dog" , "Energetically playful" , "In high spirits" , "Frolicsome" , "Playful, full of energy" .)