Billy, needing haircut, is a slow racer (5,4)

I believe the answer is:

hairy goat

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'a slow racer' is the definition.
I don't know anything about this answer so I cannot judge whether it can be defined by this definition.

'billy needing haircut' is the wordplay.
'billy' becomes 'goat'.
'needing' says to put letters next to each other.
'haircut' becomes 'hairy' (I can't justify this - if you can you should believe this answer much more).
'goat' put after 'hairy' is 'HAIRY GOAT'.

'is' is the link.

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

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