INFEASIBLE

impracticable, infeasible, unfeasible, unworkable

(adjective) not capable of being carried out or put into practice; “refloating the sunken ship proved impracticable because of its fragility”; “a suggested reform that was unfeasible in the prevailing circumstances”

Source: WordNet® 3.1

Etymology

Adjective

infeasible (comparative more infeasible, superlative most infeasible)

not feasible

Antonym: feasible

Usage notes

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.

Source: Wiktionary

In*fea"si*ble, a.

Definition: Not capable of being done or accomplished; impracticable. Glanvill.

Source: Webster’s Unabridged Dictionary 1913 Edition