Over-used phrase (6)
I believe the answer is:
cliche
'over-used phrase' is the definition.
(I've seen this before)
This is all the clue.
(Other definitions for cliche that I've seen before include "Hackneyed expression" , "Tag" , "Saying made tedious through over-use" , "Over-used saying, hackneyed phrase" , "Platitude" .)