Application processes that were invoked by the Application Builder can conveniently be killed if needed.
To kill all such processes, choose
Build > Kill All
or click the 
button.
To kill just one such process choose Build > Kill Application . This raises a menu listing the invoked applications that are still running in the chronological order in which they were invoked. Select one item from the menu to kill that process.
LispWorks IDE User Guide (Macintosh version) - 25 Nov 2011