Toss
This term refers to the attempt to engage in rotation without the ability to maintain one's center. This flaw results in destabilization of structure and balance, and loss of power as a consequence. In Chen Style Taijiquan Practical Method “tossing” is considered one of the ills of the practice, a weakness to be overcome if progress is to occur. http://practicalmethod.com/2010/11/tossing-online-video-trailer/
Source: https://practicalmethod.com/?p=7684