The story
- Anglian Old English · derived fromġesibness
- West Midland Middle English · derived fromsibnesse
- Middle Scots · derived fromsibnes
- Scots · borrowed fromsibness
- English todaysibness
Probably borrowed from Scots sibness, from Middle Scots sibnes, perhaps from West Midland Middle English sibnesse, perhaps itself from Anglian Old English ġesibness; compare West Frisian sibbens. By surface analysis, sib + ness.
Etymology from Wiktionary, CC BY-SA 4.0.