In MacOS here are two ways to kill processes in one hit. I'll use Google Drive as an example.
List process IDs (optional, useful to query beforehand or verify afterwards):
ps aux | grep "Google Drive" | awk '{print $2}'
Kill:
ps aux | grep "Google Drive" | awk '{print $2}' | xargs kill -9
-or-
sudo killall -9 "Google Drive"
The above two perform the same task.