Instable
Pronunciation : In*sta"ble
Part of Speech : a.
Etymology : [L. instabilis: cf. F. instable. See In- not, and Stable, a., and cf. Unstable.]
Definition : Defn: Not stable; not standing fast or firm; unstable; prone to change or recede from a purpose; mutable; inconstant.
Source : Webster's Unabridged Dictionary, 1913