[draven]

The only workaround I can think of is: don't use the clipboard then.

With pass you can also display the password on the console so you can retype it, but if you're running in an X session you're potentially screwed anyway.

[Widdershin]

If you wanna get real paranoid, displaying it on your screen isn't the best idea.

https://en.wikipedia.org/wiki/Van_Eck_phreaking