ASTATIC
astatic
(adjective) not static or stable
Source: WordNet® 3.1
Etymology
Adjective
astatic (comparative more astatic, superlative most astatic)
Not static or stable; unsteady, unstable.
Losing polarity, as a magnetic needle.
(medicine) Of or pertaining to astasia.
Source: Wiktionary
A*stat"ic, a. Etym: [Pref. a- not + static.] (Magnetism)
Definition: Having little or no tendency to take a fixed or definite
position or direction: thus, a suspended magnetic needle, when
rendered astatic, loses its polarity, or tendency to point in a given
direction. Astatic pair (Magnetism), a pair of magnetic needles so
mounted as to be nearly or quite astatic, as in some galvanometers.
Source: Webster’s Unabridged Dictionary 1913 Edition