General understanding:
* Comprehend
* Grasp
* Perceive
* Apprehend
* Recognize
* Realize
* See
* Get
* Know
Empathetic understanding:
* Relate to
* Feel for
* Sympathize with
* Be in tune with
Intellectual understanding:
* Analyze
* Interpret
* Decipher
* Deduce
* Discern
* Figure out
Practical understanding:
* Learn
* Master
* Acquire
* Get the hang of
* Be familiar with
Other synonyms:
* Appreciate
* Acknowledge
* Be aware of
* Be conscious of
* Be mindful of
The best synonym to use will depend on the context and the specific meaning you want to convey.