1. broken, ruined, or not working properly
Usage: informal; chiefly Irish and British English
2. exhausted or worn out
Usage: informal; chiefly Irish and British English

Examples

• The old car engine is completely banjaxed.
• My phone got banjaxed after I dropped it in water.
• After running a marathon, I felt absolutely banjaxed.
• The washing machine is banjaxed and needs repair.
• He came home banjaxed from a long day of work.