at the back of your mind
US /æt ðə bæk əv jʊər maɪnd/
UK /æt ðə bæk əv jʊər maɪnd/

1.
心の片隅に, 頭の片隅に
a thought or worry that you have but that you are not thinking about consciously
:
•
The thought of the upcoming exam was always at the back of her mind.
来るべき試験のことが常に彼女の心の片隅にあった。
•
He had a nagging feeling at the back of his mind that he had forgotten something important.
彼は何か重要なことを忘れたという嫌な予感が常に心の片隅にあった。