Out of character in play, I act badly (8)
I believe the answer is:
atypical
'out of character' is the definition.
(I've seen this before)
'play i act badly' is the wordplay.
'badly' indicates anagramming the letters.
'play'+'i'+'act'='playiact'
'playiact' with letters rearranged gives 'ATYPICAL'.
'in' acts as a link.
(Other definitions for atypical that I've seen before include "Uncharacteristic" , "Abnormal, aberrent." , "Not conforming to a type" , "Not characteristic" , "Not representative or conforming to the norm" .)