Play, Act I cast finding unusual (8)
I believe the answer is:
atypical
'unusual' is the definition.
(similar in meaning)
'play act i cast' is the wordplay.
'cast' is an anagram indicator (letters are dispersed or cast around).
'play'+'act'+'i'='playacti'
'playacti' is an anagram of 'ATYPICAL'.
'finding' acts as a link.
(Other definitions for atypical that I've seen before include "Irregular" , "Nonconformist" , "exceptional" , "Not normal" , "Nonconforming" .)