Luckily for aunt breaking television: there's one left (11)
I believe the answer is:
fortunately
'luckily' is the definition.
(synonyms)
'for aunt breaking television there's one left' is the wordplay.
'breaking' is an anagram indicator.
'television there' becomes 'ylet' (I can't explain this - if you can you should give a lot more credence to this answer).
'one left' says the letters should be written in reverse.
'ylet' in reverse letter order is 'tely'.
'aunt' with letters rearranged gives 'tuna'.
'for'+'tuna'+'tely'='FORTUNATELY'
(Other definitions for fortunately that I've seen before include "As luck would have it" , "By good luck" , "Luckily" .)