English Vocabulary Flash Cards @ englishpdf.com and englishteststore.com File 311 insufficiency (n) Inadequacy insufficient (adj) Inadequate for some need, purpose, or use insular (adj) Pertaining to an island insulate (v) To place in a detached state or situation insuperable (adj) Invincible insuppressible (adj) Incapable of being concealed insurgence (n) Uprising insurgent (n) One who takes part in forcible opposition to the constituted authorities of a place