Don-dam-pa’i ngo-bo
[translation-eng] {Hopkins} ultimate-non-nature; ultimate-naturelessness
This is one of the three non-natures: character-non-nature (mtshan nyid ngo bo nyid med pa, utpattiniḥsvabhāvatā); production-non-nature (skye ba ngo bo nyid med pa, utpattiniḥsvabhāvatā); ultimate-non-nature (don dam pa ngo bo nyid med pa, paramārthaniḥsvabhāvatā). ""Ultimate-non-nature"" has two meanings. The first meaning refers to thoroughly established natures, which are the actual ultimate-non-nature since they are both
(1) the ultimate as the object of observation by a path of purification and
(2) the very non-nature, that is, the absence of the opposite of emptiness in phenomena. The second meaning refers to fact that other-powered natures are not the ultimate; just as other-powered natures are natureless in terms of (self-)production, so they are natureless in terms of the ultimate — that is to say, they lack being that nature which is the ultimate. Thus, thoroughly established natures are ""ultimate-non-natures,"" and other-powered natures are also ""ultimate-non-natures"" but for different reasons--the first is the ultimate and the second is not.
Source : Jeffrey Hopkins' Tibetan-Sanskrit-English Dictionary