1. in a way that causes extreme physical or mental pain
2. in a way that is extremely slow or difficult to endure

Examples

• The injured athlete moved agonizingly slowly across the field.
• She waited agonizingly for the test results to arrive.
• The final minutes of the game passed agonizingly slowly.
• He was agonizingly close to winning the championship.
• The decision was agonizingly difficult to make.
• The movie was agonizingly boring and seemed to last forever.