Crossword Genius

Adult female has messed about with speed (4,5,5)

Ross

I believe the answer is:

full steam ahead

'with speed' is the definition.
(full steam ahead means at full speed)

'adult female has messed' is the wordplay.
'messed' indicates an anagram (letters get messed up).
'adult'+'female'+'has'='adultfemalehas'
'adultfemalehas' is an anagram of 'FULL STEAM AHEAD'.

'about' acts as a link.

I've seen this clue in The Guardian.
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