Are there any other words which give the meaning not enrolled?
I am searching for a single word which means never being enrolled in the first place, or not being a member of some class/school/institution etc.
I know of the word unenrolled but I don't know whether it's correct or not as I cannot find it's meaning in some dictionaries like Oxford advanced learners dictionaries, Cambridge dictionary etc. Though I have found its meaning as to undo the enrollment of, in some dictionaries. I have found some other words like disenroll which imply the same meaning.
Suppose I want to say students who are not enrolled in a class, how can I say it using alternative for "not enrolled"?
But I can't find any word which implies the meaning never enrolled in the first place.
Are there any words which fits in the context? If so, can anyone please tell me which words I can use instead of not enrolled?