Fairly good (9)
'fairly good' is the definition.
(I've seen this before)
This is all the clue.
(Other definitions for tolerable that I've seen before include "Passable" , "Fairly good" , "Bearable" , "Adequate" , "Mediocre" .)
(Other definitions for not so bad that I've seen before include "Fair" , "Reasonably OK" , "Reasonable" .)