This is not the usual answer but this is my answer.
This answer is personal but obvious for any French/English speaker.
In French you can write this name differently.
Thibault, Thibaut, Thibaud and Thibauld.
- In French the English "e" is "i" so instead of reading "Thi" you should read "The".
About the second part of this name, remember you can wrtite it, Bault, Baut, Baud and Bauld. The English "o" can be writen in French "o" or "Au".
The word Bold become obvious so the real meaning of this name is simply The bold, Thebold. "Le Brave".
Another Hint, remember how the French are writing "the old alliance" between France and Scottland, "the Auld alliance".
If you like my answer feel free to use it and to write it in correct English.
Regards
Thibault