What does your surname mean?

A query sent to our local society asked "What is the origin and meaning of my surname?" So I went looking on the web, and found:

At www.last-names.net, you can put your surname into a search box and click Search. The result is a definition of the origin and meaning of the surname, such as:

Search results for: Seaver
(origin: Gaelic.)
Saibher, rich;
Sever, local, a town in France.

Or for another name in my ancestry:

The heading for the page says:

Find the ethnic origin and meaning of last names.
Surname dictionary and genealogy helps include names
of Irish, German, English, French, Italian, and Jewish descent.

However, when I input a number of German sounding names, like Carringer/Geringer, Auble, Karcher, Rau, etc., I got no definition. Likewise, English names like Richman, Hildreth and Marshman result in no definition.

There are lists of nationalities in the left hand column so that you can see what is available for each.

The page does helpfully provide numbers for occurrences of the name in some of the Ancestry.com databases, which are interesting and not helpful, but there are no links.

There are other sites like this, I think, so maybe I'll do a bit more looking.