A theoretical study or explanation is based on or uses the ideas and abstract principles that relate to a particular subject, rather than the practical aspects or uses of it.
theoretical physics.
理论物理。
There is no theoretical model to explain the impact of inflation on growth.
没有理论模式来解释通胀对增长的影响。
If you describe a situation as a theoretical one, you mean that although it is supposed to be true or to exist in the way stated, it may not in fact be true or exist in that way.
This is certainly a theoretical risk but in practice there is seldom a problem.
这在理论上肯定有风险,但在实践中却很少出问题。
These fears are purely theoretical.
这些恐惧纯属理论上的。