1. hit or struck something, especially lightly or accidentally
Usage: informal
2. became extremely tired or exhausted, especially during physical activity
Usage: informal; sports

Examples

• She bonked her head on the low ceiling.
• The ball bonked off the wall and rolled away.
• He bonked the table with his knee as he walked by.
• The cyclist bonked after 50 miles and had to stop.
• I totally bonked during the marathon and couldn’t finish.
• The runner bonked because she didn’t eat enough carbs.
• My energy levels crashed and I bonked completely.