Crossword Genius

Be thoroughly malicious and toss one word out (2,4,5)

Ross

I believe the answer is:

do ones worst

'be thoroughly malicious' is the definition.
(to do one's worst is to be as nasty as possible)

'toss one word out' is the wordplay.
'out' indicates an anagram (out can mean wrong or inaccurate).
'toss'+'one'+'word'='tossoneword'
'tossoneword' is an anagram of 'DO ONES WORST'.

'and' acts as a link.

(Another definition for do ones worst that I've seen is " Be as evil as possible".)

I've seen this clue in The Guardian.
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