Don turned up with heavy weight (3,2)
I believe the answer is:
put on
'don' is the definition.
(I know that don can be written as put on)
'turned up with heavy weight' is the wordplay.
'turned' shows that the letters should be reversed in order.
'with' means one lot of letters go next to another.
'heavy weight' becomes 'ton' (a ton weighs a lot).
'up' reversed gives 'pu'.
'pu'+'ton'='PUT-ON'
(Other definitions for put on that I've seen before include "Apply (to a surface) - present (on stage)" , "Don clothes or stage play" , "Assume < present" , "in an unnatural way" , "Increase as with weight" .)