At a quick pace or at hand; moving swiftly or readily available (archaic/dialectal usage).
From 'a-' (on/in) + 'pass' (pace or movement), forming an adverbial construction meaning 'in a passing/swift manner.' This is an obsolete English formation rarely used after the 17th century.
Apass is one of those wonderful archaic words that shows how English used to pile prefixes and particles together more freely—modern English simplified constructions like 'apass' to just 'at pace' or 'swiftly,' but the word survives in historical texts and poetry.
Complete word intelligence in one call. Free tier — 50 lookups/day.