Broken chain apt to be under stress (2,1,5)
I believe the answer is:
at a pinch
'stress' is the definition.
I don't know anything about this answer so I cannot judge whether it can be defined by this definition.
'broken chain apt to be under' is the wordplay.
'broken' is an anagram indicator.
'to be under' says to put letters next to each other.
'chainapt' is an anagram of 'AT A PINCH'.
Can you help me to learn more?
(Other definitions for at a pinch that I've seen before include "in case of emergency", "in a crisis?", "If absolutely necessary", "In time of difficulty or necessity - nip it", "under pressure".)