Is a morpheme bound or is it free: any online source?
As far as I know, this is not a free combination.
China has official word statistics. This is used to guide everyday language. The use of words is generally restricted by these official data. If some morpheme combinations are used privately, the resulting words may be too strange to be understood by anyone.
Put another way, the combination of morphemes in Chinese is constrained by words or idioms. Free morpheme combinations can only be used for personal use, or in certain situations (such as emergencies or colloquial expressions).
You can check this online Chinese word website
http://www.xh.5156edu.com/