Female or male class (4)

I believe the answer is:

form

'class' is the definition.
('form' can be a synonym of 'class')

'female or male' is the wordplay.
'female' becomes 'f' (abbreviation).
'male' becomes 'm' (common abbreviation).
'f'+'or'+'m'='FORM'

(Other definitions for form that I've seen before include "Criminal record (colloq.)" , "Hare's home - something to be filled in" , "Acceptable conduct" , "Class - hare's home" , "Part of school" .)

I've seen this clue in The Telegraph.

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