Stage entertainer is tense after python uncoiled (9)
I believe the answer is:
hypnotist
'stage entertainer' is the definition.
(I've seen this before)
'is tense after python uncoiled' is the wordplay.
'tense' becomes 't' (abbreviation used in many dictionaries).
'after' means one lot of letters go next to another.
'uncoiled' indicates an anagram.
'python' is an anagram of 'hypnot'.
'is'+'t'='ist'
'ist' put after 'hypnot' is 'HYPNOTIST'.
(Other definitions for hypnotist that I've seen before include "Mesmerising person" , "One who mesmerises" , "stage entertainer" , "charmer" , "Mesmeriser" .)