Alas, is about to attack! (6)

I believe the answer is:

assail

'to attack' is the definition.
(synonyms)

'alas is about' is the wordplay.
'about' indicates an anagram.
'alas'+'is'='alasis'
'alasis' is an anagram of 'ASSAIL'.

(Other definitions for assail that I've seen before include "Aggressively attack" , "Launch an attack" , "Molest or harass" , "Go for" , "Criticise severely" .)

I've seen this clue in the Sydney Morning Herald.

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