Unusual new Roman lab (8)
I believe the answer is:
abnormal
'unusual' is the definition.
(similar in meaning)
'new roman lab' is the wordplay.
'new' indicates anagramming the letters.
'roman'+'lab'='romanlab'
'romanlab' is an anagram of 'ABNORMAL'.
(Other definitions for abnormal that I've seen before include "Unusual, atypical" , "Deviant or unnatural" , "Deviant, different from the usual" , "Peculiar, unnatural" , "Anomalous" .)