Little thanks received by study on male function (9)
I believe the answer is:
cotangent
'function' is the definition.
(cotangent is a kind of function)
'little thanks received by study on male' is the wordplay.
'little thanks' becomes 'ta' (short way of saying 'thank you').
'received by' means one lot of letters goes inside another.
'study' becomes 'con' (I've seen this before).
'on' is a charade indicator (letters next to each other).
'male' becomes 'gent' (gent is a kind of male).
'ta' inserted into 'con' is 'cotan'.
'cotan'+'gent'='COTANGENT'
(Other definitions for cotangent that I've seen before include "Maths function" , "Mathematician's function" , "In triangular relationship" , "proportion" , "Mathematical ratio" .)