An investor is an individual or entity that actively participates in the financial market to increase their wealth. Synonyms for investor include money provider, capital provider, or financial market customer. The addition of "private" distinguishes the economic entity from professional and semi-professional investors.
"Private investors are all investors who are neither professional nor semi-professional investors." (§ 1 Absatz 19 Nr. 31 Kapitalanlagegesetzbuch/KAGB).