Hose connector Query

[Mr Sparkle]

I've removed the waste from my washing machine that connects to the hose connector (image below)..

What is the easiest way to cap this off? What part do is required?

Also, I have a small leak at the nut... When I took the part apart, I noticed that there was no washer in mine... Should one be there?

 

[stem]

You can buy a blanking cap specifically for the purpose.....

...and the original should have a seal in it somewhere.

 

[Mr Sparkle]

Topman! Thanks