Skittish comes from Middle English skittish, probably from the base of skit ('to move rapidly, caper'), of Scandinavian origin, akin to Old Norse skjota ('to shoot'). The historical chain includes Old Norse skjota. Older glosses in the chain include "to move rapidly, caper" and "to shoot", which help explain the semantic range of the modern word. Morphologically, skittish is best read as borrowing, yielding an English adjective shaped by both form history and later usage. In current English it functions as an adjective, with the sense "nervous and easily startled or excitable". English derivatives include skittishly and skittishness; related forms include skit and skitter. The result is an English adjective whose etymology preserves the older forms while supporting the word's specialized modern meaning.