What does unfeasible mean?
Unfeasible is an adjective meaning that something cannot be achieved or carried out, especially because the necessary conditions, resources, time, or methods make it impossible in practice. It is commonly used in technical, business, planning, and engineering contexts, as in “technically unfeasible” or “economically unfeasible.” The word conveys more than a simple lack of convenience: it indicates that an objective or proposed course of action cannot realistically be accomplished. Unfeasible is valid in both British and American English, although it is more strongly associated with British usage, while infeasible is the more familiar spelling in American English. The word is related to feasible, meaning possible or practicable, and appears in a family of related forms such as feasibility and infeasibility. It is a precise and useful term when discussing technical limitations, operational constraints, or projects whose requirements cannot realistically be met.
adjectiveNot possible or not practicable to achieve or carry out.
- Unable to be achieved, carried out, or made to work in practice.
"Finishing the migration by Friday was unfeasible because the test suite was still failing."
"Finishing the migration by Friday was unfeasible because the test suite was still failing."
"The committee concluded that repairing the bridge without closing it would be unfeasible."
A word for something impossible in practice can itself have a spelling dilemma: both unfeasible and infeasible are valid, but one is far more familiar.
Reviewed by Deb Chak, Editor. AI-assisted content curated by RJS Tech Solutions LLP.
Where does unfeasible come from?
Unfeasible was formed by adding the English prefix un-, meaning “not,” to feasible, an adjective derived from French faisable. French faisable comes from faire, “to do or make,” and ultimately from Latin facere, “to make.” The same Latin root underlies related English forms such as feasible, feasibility, and infeasible. The prefixed form unfeasible developed as a less common alternative to the now more familiar infeasible.
How unfeasible is actually used
The word tends to appear in formal, technical, planning, or business contexts. It often describes an option that is impossible in practice rather than something ruled out by an abstract logical contradiction.
Easily confused with unfeasible
Unfeasible and infeasible have the same meaning, but infeasible is the more common spelling in American English, while unfeasible is especially associated with British usage.