You're either realtime or you're not. If you have hard and fast time requirements to perform certain actions then you're real time. (e.g. 3 ms. to decide whether or not to turn the cruise missile or it hits a hospital). There is no 'soft' realtime.
Systems are not divided into cruise missile control systems and everything else. There is a continuum in between. A phone system where the calls need to routed in the 100 milliseconds or less 99.999% of the time is acceptable for example, while one where no such guarantees can be provided at all is not acceptable. It is not a realtime systems but it is pretty close, so it would be called soft realtime.