In evolution thermodynamics, anti-entropy is a loose term associated with effects or processes opposite that of entropy, namely order, organization, and improbability as opposed to that of disorder, disorganization and probability. [1] It expresses the ascending primacy of life over entropy, where life is defined as a kind of anti-entropic or negative entropy process. [1] This particular terminology is often considered a post-Teilhardian expression, in that it was used significantly by French scientific-religious philosopher Pierre Teilhard, becoming a common term in 1967. [1]

In an unpublished manuscript dated November 19, 1951 (dedicated to Julian Huxley),Huxley), in a section titled "The Transformation, starting with Man, of the Process of Evolution", Teilhard defines anti-entropy as "an effect of changes that are seized, draws a portion of matter in the direction of continually higher forms of structurization and centration." [2]

References
1. Cowell, Sion. (2001). The Teilhard Lexicon: Understanding the Language, Terminology and Vision of Pierre Teilhard de Chardin: The First English-Language Dictionary of his Writin. (pg. 125). Sussex Academic Press.
2. Telhard, Pierre. (1976). Activation of Energy, (pgs. 302-3). New York: Harvest Book.

Further reading
● Bailly, Francis and Longo, Guiseppe. (2009). “Biological Organization and Anti-Entropy.” Journal of Biological Systems, Vol. 17, No. 1.