To draw attention to tirade is outrageous (8)
I believe the answer is:
flagrant
'outrageous' is the definition.
(flagrant can mean outrageous or blatant)
'to draw attention to tirade' is the wordplay.
'to draw attention to' becomes 'flag' (as in to flag or mark something).
'tirade' becomes 'rant' (both can mean an angry outburst).
'flag'+'rant'='FLAGRANT'
'is' is the link.
(Other definitions for flagrant that I've seen before include "Being shameless" , "'Conspicuous, glaring (8)'" , "Crying" , "Barefaced" , "Very bad and obvious, say offence" .)