secret diary

Translations
секретный дневник
She hid her secret diary under the bed.
Она спрятала свой секретный дневник под кроватью.
Definitions
A secret diary is a personal journal where an individual records their thoughts, feelings, experiences, and reflections, often kept private and not intended for others to read.
Words
diary

noun
дневник
secret

adjective
секретный