absorbed in thought

Translations
погружённый в размышления
She was so absorbed in thought that she didn't hear the phone ring.
Она была так погружена в размышления, что не услышала звонка телефона.
Definitions
Engaged in deep contemplation or reflection, often to the extent of being unaware of one's surroundings.
Words
thought

noun
мысль
absorbed

adjective
поглощённый