Tax song (6)
I believe the answer is:
strain
I believe this clue is a double definition.
'tax' is the first definition.
(both can mean to demand a lot from)
'song' is the second definition.
(I know that song can be written as strain)
(Other definitions for strain that I've seen before include "Pass through a filter" , "Tension - tune" , "line of ancestry" , "Remove by passing through a filter" , "Pour through a sieve" .)