How do I kill an application in Mac terminal?

Open the Terminal utility in the Utilities folder, type “top” and press Return. Select the program needing to be closed under the column COMMAND, noting that its name may be shortened. Find the PID - the number to the left of the program’s name and note it down. Type “q” to exit and return to the command line, then type “kill ###”, using the PID in place of the ###. If it still won’t respond, type “sudo kill -9###”, again using the PID in place of the ### in this example. More detail and images on this process are found above in this article.