keep to oneself
- avoid contact with others, isolate oneself
- keep something to oneself: not spill the beans
Wiktionary
verb
- To purposely avoid interaction with others; to be introverted.
“She preferred to keep to herself after her husband died.”
“I've done no harm, I keep to myself / There's nothing wrong with my state of mental health”
- To refrain from telling or giving; to keep secret, or refuse to share.
“keep oneself to oneself”
“Then he fell to gabbling strange and dreadful things which were not clearly understandable, and which the doctor admonished them to keep to themselves.”