Imperturbable
Pronunciation : Im`per*turb"a*ble
Part of Speech : a.
Etymology : [L. imperturbabilis; pref. im- not + perturbare to disturb: cf. F. imperturbable. See Perture.]
Definition : Defn: Incapable of being disturbed or disconcerted; as, imperturbable gravity.
Source : Webster's Unabridged Dictionary, 1913