1. created or performed without preparation or planning; made up on the spot
2. made from whatever materials are available; makeshift

Examples

• The comedian gave an improvised performance based on audience suggestions.
• She delivered an improvised speech when the microphone failed.
• The children built an improvised fort using blankets and chairs.
• His improvised solution saved the day when the equipment broke.
• The jazz musician played an improvised solo that amazed the crowd.
• They created an improvised shelter from branches and leaves.
• The actor’s improvised lines were funnier than the script.