Nothing put in tin for untidy person (6)
I believe the answer is:
sloven
'untidy person' is the definition.
(I've seen this in another clue)
'nothing put in tin' is the wordplay.
'nothing' becomes 'love' (love is zero in tennis).
'put in' indicates putting letters inside (back).
'tin' becomes 'Sn' (Sn is the chemical symbol for tin).
'love' put within 'sn' is 'SLOVEN'.
'for' is the link.
(Other definitions for sloven that I've seen before include "slattern" , "scruffy sort" , "Habitually negligent person" , "Novels for an untidy woman" , "scruffy individual" .)