'jagged' originates from Middle English, specifically the word 'jagge' (from the base 'jag'), where 'jag' meant 'a sharp point, notch, or projection'.

'jagged' changed from the Middle English word 'jagge' and formed by adding the adjectival suffix '-ed' to produce 'jagged'; the adverb 'jaggedly' was later formed by adding '-ly' to the adjective.

Initially it meant 'having notches or sharp projections', and over time it retained that basic sense; 'jaggedly' developed as the adverbial form meaning 'in a jagged manner'.