不干己事不张口一问摇头三不知 literally translates as [About] matters [that] don't concern [you], do not open [your] mouth, [and] when questioned, always shake [your] head “No.”

Figuratively, this means: It is best to remain reticent about other people's affairs and to refuse to make any comment on matters that don't concern you.

余計なお世話 suggests that you do not give unwanted help or advice to someone.

The Japanese characters break down this way:
余計 (yokei) too much, unnecessary, extraneous, abundance, surplus, excess, superfluity.
な (na) connecting article. お世話 (osewa) help, aid, assistance.

Note: Because this selection contains some special Japanese Hiragana characters, it should be written by a Japanese calligrapher.

興隆 is a kind of prosperity that applies to a business. Something great to hang behind your desk if you are a small or large business owner. Doing so says that you either are a booming business or you wish success and prosperity for your business.

Can also be translated as thriving, flourishing, brisk business, and other words related to prosperity in business.

A good meaning in China but is a little antiquated in Japanese.

See Also:  Prosperity