$ sudo swapoff -a
If you want to permanently disable swap space, you may want to free disk space allocated to swap space. To do this, first remove auto-mounting swap at boot:
$ sudo vim /etc/fstab
In the file, comment out the line that is mounting the swap space. It should be obvious. In my case, it reads like:
#/dev/mapper/ubuntu--vg-swap_1 none swap sw 0 0
Now, you may want to use gparted or any other utilities and tools to free up the space!