Yes, it is possible to apply for the 2nd semester. However, only for the summer semester. The application period (usually December 1 to January 15) can be found here:

https://www.fu-berlin.de/en/studium/bewerbung/frist-master/index.html

Please note that for a successful application you must meet all the same admission criteria as for the first semester! If you apply to the second semester, you must also prove that you have the level of knowledge from the first semester.