keep (one's) own counsel

Translations
держать (свои) мысли при себе
She tends to keep her own counsel and rarely shares her thoughts.
Она склонна держать свои мысли при себе и редко делится ими.
Definitions
To keep one's thoughts, opinions, or plans to oneself and not share them with others.
Words
counsel

noun
совет
keep

verb
держать
own

adjective
собственный