Saw not going to lose teeth, originally (6)
I believe the answer is:
saying
'saw' is the definition.
(I've seen this before)
I cannot understand how the rest of the clue works.
Can you help me to learn more?
(Other definitions for saying that I've seen before include "Adage, maxim" , "Speaking; adage" , "Articulating" , "Uttering" , "Apophthegm" .)