university word

I have never heard the word conditional used like this. Things like offers can be conditional, but people can not be.

In the United States, the phrase academic probation is used for the consequences of a low GPA. For example, Columbia University has the following policy:

Students may be placed on academic probation for the following reasons: [other reasons] ... or earning a term or cumulative grade point average below 2.0...

You may be referring to a conditional offer of admission which is an offer of admission, usually to a school, conditioned on performance. For example, you could be offered admission to a university conditioned on attaining a certain GPA when you graduate high school.