Meaning

adverb to a high degree or extent; favorably or with much respect

adverb at a high rate or wage

adverb in a high position or level or rank

originFrom Middle English hiȝly, heȝly, heyȝliche, from Old English hēalīce (“highly”), equivalent to high + -ly. Cognate with Dutch hoogelijk (“highly”), German höchlich (“highly”), Danish højlig (“highly”), Swedish högligen (“highly”).

Etymology from Wiktionary, CC BY-SA 3.0