infeasible

From in- +‎ feasible. Cognate to French infaisable.

infeasible (comparative more infeasible, superlative most infeasible)

1. Not feasible.

   Antonym: feasible

   • 2018 February 21, Dan Shive, El Goonish Shive (webcomic), Comic for Wednesday, Feb 21, 2018:

     "With magic in limited use and hidden, it was possible to enhance the various magic resistances of humans, and to keep certain forms of magic from being possible. If magic enters common usage, this interference becomes infeasible."

   • 2022 February 9, “Network News: Prime Minister "blew nearly £1m" on Northern Ireland bridge study”, in RAIL, number 950, page 20:

     Labour's Shadow Transport Secretary Louise Haigh said: "There is a cost-of-living crisis, and the Prime Minister blew nearly £1m of public money on an utterly infeasible vanity project. That's enough to fill 18,000 potholes. This shows the Tories' sheer disrespect for public money."

Usage varies between infeasible, unfeasible, and not feasible – all are synonymous, but usage varies regionally and over time, and unfamiliar usage is often jarring or sounds wrong. Today infeasible is somewhat more common in American usage, though traditionally unfeasible was more common, being surpassed by infeasible in the late 1970s (in both America and Britain). Of these, infeasible is etymologically pure – formed of French/Latin roots – and cognate to French infaisable, while unfeasible is hybrid, combining Germanic un- with Latinate feasible.^[1]

• “infeasible”, in Lexico, Dictionary.com; Oxford University Press, 2019–2022.