I went around about this with a player...
An ork with the Human-Looking quality will look at first glance like a burly, hairy human. An elf will look like a skinny human with high cheekbones. A dwarf will look like a short burly hairy human.
The quality is not a a perfect disguise. And why would you want it to be, anyway? As the description in the BBB states, it can cause the character trouble, too.
I had a player who insisted it was an impenetrable disguise. To what purpose, I don't know. "Nobody knows I'm secretly a dwarf, tee-hee-hee."
The major rules issue is that a chacter with this quality looks enough like a human that he doesn't suffer penalties when dealing with racists. The racists may not realize that the character is a meta, or they might think that the character is human enough to be acceptable.