A "vague memory" refers to a recollection of something that is not very clear or detailed. It is when you remember something, but the details are not clear in your mind.
Sentences with «vague memory»
Between all the talk about a shortage, along with vague memories of its lack of availability last year, I figured why not? (iwasborntocook.com)
We won't remember a handful of other players at all, with vague memories of some of the rest. (sbnation.com)
The only vague memory he can summon in his mind is that of a sculpture atop a hill, depicting human hands reaching towards the sky. (windowspcapp.com)