How to stop a process in Terminal

Ctrl + C

Ctrl + C is a the standard *nix way of signaling a process to abort.

Try Ctrl + C. Also, Ctrl + Z might help if you want to suspend a process.

For further information, man kill.

If you're curious about the difference between suspend and terminate, this answer is a good starting point; the TL;DR version is, a suspended process can be resumed later and its execution can continue. A terminated (and killed) process will be gone.