Tipping point?
I believe the answer is:
jar
'tipping point?' is the definition.
(I've seen this in another clue)
This is the entire clue.
(Other definitions for jar that I've seen before include "Glass of beer (colloq.)" , "Wide-mouthed vessel" , "Pint glass of beer, perhaps" , "Grate" , "Shock; container" .)