1. A target that is moved as one attempts to hit it with bullets from a firearm. My accuracy is not the greatest, so I'm definitely not ready to work with running targets.
2. Something that frequently changes, making it difficult to achieve, define, understand, etc. Sometimes, work in the medical field it's so fast-paced that it feels like you're trying to hit a running target.
Farlex Dictionary of Idioms. © 2015 Farlex, Inc, all rights reserved.