To single out is to pick one person from the group for special treatment. Single out for praise, singled out for blame, do not single anybody out.
It works for praise and punishment alike, and the discomfort is the same either way, since being singled out separates you from everybody else. The parts split around an object.
1phrasesingle outTo pick one person from the group for special treatment.
“Please don't single out one pupil for blame when the whole class was involved.”
single out is a choosing.
Single plus out, recorded from 1629, from the old sense of separating one animal from a herd.
From single + out. 1629.
Etymology from Wiktionary, CC BY-SA
Practised in Phrasal Verbs