1. impossible to defeat, overcome, or capture; unconquerable
Usage: formal; literary

Examples

• The fortress was considered inexpugnable due to its strategic location on the cliff.
• Her inexpugnable spirit helped her overcome every obstacle in her path.
• The team’s inexpugnable defense prevented any goals throughout the tournament.
• His inexpugnable faith sustained him through the most difficult times.
• The castle’s inexpugnable walls had never been breached in centuries of warfare.
• She maintained an inexpugnable optimism despite repeated setbacks.