[Probably short for French empestrer, to constrain, embarrass (probably also influenced by PEST), from Old French, from Vulgar Latin *impāstōriāre : Latin in-, in; see IN-² + Vulgar Latin *pāstōria, a hobble, from Latin, feminine of pāstōrius, of a herdsman (from pāstor, herdsman; see pā- in the Appendix of Indo-European roots).]