ex*pi*ate v. [trans.] atone for (guilt or sin): their sins must be expiated by sacrifice. ex*pi*a*ble adj. ex*pi*a*tion n. ex*pi*a*tor n. ex*pi*a*to*ry adj. late 16th cent. (in the sense 'end (rage, sorrow, etc.) by suffering it to the full'): from Latin expiat- 'appeased by sacrifice', from the verb expiare, from ex- 'out' + piare (from pius 'pious').