Related Clues:

• With 40-Across, modern
• Unaccustomed (to)
• Unused
• Groundbreaking
• Hot off the presses
• Cutting-edge
• Untrained
• Never used
• Unfamiliar, as territory
• Opposite of 53-Down
• Out of the ordinary
• Spanking follower
• Recent
• Ad catchword
• Unexplored