immobile adj.

word-forming element meaning "not, opposite of, without" (also im-, il-, ir- by assimilation of -n- with following consonant, a tendency which began in later Latin), from Latin in- "not," cognate with Greek an-, Old English un-, all from PIE root *ne- "not."

In Old French and Middle English often en-, but most of these forms have not survived in Modern English, and the few that do (enemy, for instance) no longer are felt as negative. The rule of thumb in English has been to use in- with obviously Latin elements, un- with native or nativized ones.

late 15c. (Caxton), "capable of movement, capable of being moved, not fixed or stationary," from Old French mobile (14c.), from Latin mobilis "movable, easy to move; loose, not firm," figuratively, "pliable, flexible, susceptible, nimble, quick; changeable, inconstant, fickle," contraction of *movibilis, from movere "to move" (from PIE root *meue- "to push away"). Sociology sense of "able to move into different social levels" is by 1927. Mobile home "large trailer permanently parked and used as a residence" is recorded by 1936. Mobile phone is by 1983.

A long-distance number tapped into an Illinois Bell car telephone glowed red on a display. Satisfied that the digits were correct, I pushed the SEND button on the phone. Familiar beeps and boops emerged from the handset. Then, before a half block of this Chicago suburb had slipped by, I was in contact with my New York office. ["Take-along Telephones," Popular Science, October 1983]