Flakiness in testing refers to the inconsistency in test results when the same tests are run multiple times. This phenomenon can be frustrating for test automation engineers as it can lead to false positives or negatives, making it challenging to trust the reliability of the tests. This can be caused by a variety of factors such as environmental changes, timing issues, or race conditions within the software being tested. To address flakiness, it is important to identify the root cause of the issue and make necessary adjustments to ensure more stable and reliable test results.