Reserved comedian, essentially shy and strained (9)
I believe the answer is:
withdrawn
'reserved' is the definition.
(similar in meaning)
'comedian essentially shy and strained' is the wordplay.
'comedian' becomes 'wit' (a witty person).
'essentially' indicates the central letters.
'and' means one lot of letters go next to another.
'strained' becomes 'drawn' (I've seen this before).
The middle letter of 'shy' is 'h'.
'wit'+'h'+'drawn'='WITHDRAWN'
(Other definitions for withdrawn that I've seen before include "Retired" , "Private" , "Shy, reserved" , "Pulled out of" , "Shrinking" .)