a short fuse
From Longman Dictionary of Contemporary Englisha short fusea short fuseBAD-TEMPEREDif someone has a short fuse, they get angry very easily → fuseExamples from the Corpusa short fuse• Wright has a short fuse, and without the goals going in his situation is worsening.• Every nerve smouldered on a short fuse.• Tom's a chap with a temper on a short fuse anyway.• You may find your temper on a short fuse when confronting your child or teenager for the umpteenth time.