"Theoretical" means something that relates to ideas or concepts rather than actual real-life situations or practical experiences. It is based on theories, hypotheses, or speculation rather than direct evidence or facts. Full definition
On the construction of theoretical model for teacher professional development. (wals2018.com)
Still, a little humility on the part of theoretical physicists might be advisable, especially toward their experimental colleagues. (scientificamerican.com)
But even though they have played an important part in theoretical physics for a long time, these correlations could hardly be measured in experiments. (sciencedaily.com)