An irregular written or printed line or mark; a squiggle.
Mid 19th century (in an earlier sense). From scriggle.
To wriggle; to struggle to move or escape. Also with adverbs, as about, away, through, etc. English regional (chiefly East Anglian) or informal in later use.
Early 18th century. Imitative of a wriggling movement, probably modelled on struggle and wriggle.