unmatchable

comparative more unmatchable · superlative most unmatchable

1. Unable to be matched.

   An edge in a graph which has a perfect matching is an unmatchable edge if no perfect matching in the graph contains that edge.

   1995, V. Balakrishnan, Network Optimization, page 228

2. Uniquely good; not approached by anything else in quality or excellence.

   Yes, the originals were fantastic, perhaps even unmatchable.

   2007 January 2, Allan Kozinn, “Celebrating Movie Musicals That Are Never Out of Date”, in New York Times

plural unmatchables

1. Something that cannot be matched.

   1 more example

   Both the matchables and the unmatchables direct us along new lines of inquiry. The matchables invite study of kinship, neighbouring, and property as advantageous ladders of social advancement, while the unmatchables invite inquiry into risk, its incidence, and the strategies young people were employing […]

   2015, Peter Baskerville, Kris Inwood, Lives in Transition: Longitudinal Analysis from Historical Sources, page 209