Whiff%
Share of swings that miss.
What Whiff% means
For pitchers, higher is better (more swings-and-misses); for hitters, lower is better. League average ~25% on swings.
What counts as a good Whiff%
Higher is better — roughly .200 is poor, .250 average, .300 good, and .350 or better elite.
Also written
whiff_rate · whiff_percent · whiff · whiffs
Source
Statcast