Slashes blouse fashioned to include measure of brilliance (8)

'slashes' is the definition.
(oblique can mean a slash symbol)

'blouse fashioned to include measure of brilliance' is the wordplay.
'fashioned' is an anagram indicator.
'to include' means one lot of letters goes inside another.
'measure of brilliance' becomes 'iq' (IQ is a measure of intellectual brilliance).
'blouse' anagrammed gives 'oblues'.
'oblues' placed around 'iq' is 'OBLIQUES'.