Sins with time on hands, son admitted (10)
I believe the answer is:
trespasses
'sins' is the definition.
(I know this)
'with time on hands son admitted' is the wordplay.
'with' means one lot of letters go next to another.
'time' becomes 't' (abbreviation).
'on hands' becomes 'repasses' (I can't explain this - if you can you should give a lot more credence to this answer).
'son' becomes 's' (genealogical abbreviation for son).
'admitted' indicates putting letters inside.
'repasses' enclosing 's' is 'respasses'.
't' put next to 'respasses' is 'TRESPASSES'.
(Other definitions for trespasses that I've seen before include "may they be forgiven!" , "Forgive them" , "Unlawfully enters" .)