Does your palm hit your touchpad when you type?
Syndaemon momentarily disables touchpad when typing, with many extra features.
$ syndaemon -i 1 -d -t -K
From ‘man syndaemon’:
-i How many seconds to wait after the last key press before enabling the touchpad.
-d Start as a daemon, ie in the background.
-t Only disable tapping and scrolling, not mouse movements, in response to keyboard activity.
-k Ignore modifier keys when monitoring keyboard activity.
-K Like -k but also ignore Modifier+Key combos.
Autostart syndaemon on XFCE
To automatically start syndaemon when you log into XFCE, you can add it to automatically starting programs.
Settings Manager: Session and Startup: Application Autostart
If there already exists syndaemon with default settings, disable it by unchecking the box.
Add.
Name: syndaemon. Command: /usr/bin/syndaemon -i 1 -d -t -K