A blend of Middle English 'scrat' and 'cratch' (both meaning to scratch) — the merged form replaced both.
To score or mark the surface of something with a sharp object; to rub skin with nails to relieve itching.
Probably a blend of 'scrat' (to scratch) and 'cratch' (to scratch), both of Germanic origin. The blended form replaced both parents. Key roots: scrat (Middle English: "to scratch"), cratch (Middle English: "to scratch").