It's a jelly/liquid/oil/vaseline type thing that lets your 'beaver' glide easier...

lu·bri·cant Pronunciation Key (lbr-knt)
n.
A substance, such as grease or oil, that reduces friction when applied as a surface coating to moving parts.
One that helps reduce difficulty or conflict.

If people would just use dictionary.com...

Ehm is there a translater.com??
I think I know what those words mean, but I don't think most of you have any idea what it's like to read in a strange language all the time.

And I got the joke without even knowing what a lubricant was. :)

And BTW if I had to guess what a lubricant was, I would have guessed it right. Actually that was what I was thinking, but I didn't bother to type it here... :D