A N'yengoren strategy was a type of attack plan known to Klingon warriors and their associates. The plan involved stealth while an opponent or target could be caught unawares.
In 2370, Jadzia Dax suggested using a N'yengoren-style attack against the Albino, but Kang condemned the idea of sneaking in and murdering the slumbering Albino in his bedroom. (DS9: "Blood Oath")
In non-canon works, Star Trek: Star Charts (p. 64) shows a Klingon star system called N'yengoren that implies an origin for the term.
According to the script, N'yengoren was pronounced as "n'yeng'O-ren".