'assoilzie' originates from Scots, ultimately from Old French and Latin influence; ultimately related to Latin 'absolvere', where 'ab-' meant 'away' and 'solvere' meant 'to loosen, release'.

'absolvere' (Latin) influenced Old French forms such as 'assolver'/'assoultier', which passed into Middle English/Scots as forms like 'assoulz'/'assoilz' and eventually the modern Scots verb 'assoilzie'.

Initially it carried the sense 'to loosen or release' (in a general sense), but over time it narrowed to the judicial/religious sense 'to free from guilt' and 'to pardon'.