അർത്ഥം : Immune to attack. Incapable of being tampered with.
							ഉദാഹരണം : 
							An impregnable fortress.
							Fortifications that made the frontier inviolable.
							A secure telephone connection.
							
പര്യായപദങ്ങൾ : impregnable, inviolable, secure, strong, unassailable