1. A device with four spikes arranged so that one always points upward, historically used to injure the feet of enemies or puncture tires.
Usage: Usually plural; also spelled 'caltrops'; Historical military weapon
2. Any obstacle or difficulty that impedes progress or causes harm.
Usage: Figurative use

Examples

• Medieval soldiers scattered caltraps across the battlefield to slow enemy cavalry.
• The protesters placed caltraps on the road to block the convoy.
• Financial regulations became caltraps for small businesses trying to expand.
• Police used caltraps to stop the fleeing vehicle.
• The company faced numerous caltraps in its attempt to enter the new market.