అర్థం : Immune to attack. Incapable of being tampered with.
							ఉదాహరణ : 
							An impregnable fortress.
							Fortifications that made the frontier inviolable.
							A secure telephone connection.
							
పర్యాయపదాలు : inviolable, secure, strong, unassailable, unattackable
అర్థం : Capable of conceiving.
పర్యాయపదాలు : conceptive
అర్థం : Incapable of being overcome, challenged or refuted.
							ఉదాహరణ : 
							An impregnable argument.
							Impregnable self-confidence.
							
పర్యాయపదాలు : inexpugnable