1. a fight with an imaginary enemy
From Greek >skiamakhia< a mock fight, from skia a shadow + makhesthai to fight]
Greek skiamachía, equivalent to skiá shadow + -machia -machy
"fighting with shadows, shadow-boxing" 1623, from Gk. skiamakhia "shadow-fighting, a sham fight" but perhaps lit. "fighting in the shade" (i.e., in school), from skia "shade, shadow" + makhe "battle."