Check breaking point (5)
I believe the answer is:
limit
I believe this is a double definition.
'check' is the first definition.
(limiting is a kind of checking)
'breaking point' is the second definition.
(I've seen this before)
(Other definitions for limit that I've seen before include "Breaking point" , "Extremity" , "Keep in" , "verge" , "Utmost" .)