Tenor goes astray - this defines the female (9)

I believe the answer is:

oestrogen

'this defines the female' is the definition.
(female hormone)

'tenor goes astray' is the wordplay.
'astray' is an anagram indicator.
'tenor'+'goes'='tenorgoes'
'tenorgoes' anagrammed gives 'OESTROGEN'.

(Another definition for oestrogen that I've seen is " Hormone".)

I've seen this clue in The Independent.

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