Python broadcast I see sounded mesmerising (8)
I believe the answer is:
hypnotic
'mesmerising' is the definition.
(I've seen this before)
'python broadcast i see sounded' is the wordplay.
'broadcast' is an anagram indicator.
'sounded' shows a homophone (sound like).
'see' sounds like 'c'.
'python' is an anagram of 'hypnot'.
'hypnot'+'i'+'c'='HYPNOTIC'
(Other definitions for hypnotic that I've seen before include "Mesmeric" , "Sleep-inducing" , "Mesmerising" , "soporific" , "Compelling" .)