I doubt this word is a Swedish derivation as it doesn't resemble any word I can think of. Gunnar Larsson 22:02, 16 February 2006 (UTC) (native Swedish speaker).
If it is not connected with a root relating to the noise boulders cause, then there is Unified Cornish BILI, [from a root *BUL-] (pebbles), that may imply a pre-Norse root for all these words. The Dutch word in the Entry is the most likely etymon, unless, of course, it be borrowed from English.
 means 'Absolutely not;  means 'Exceedingly unlikely';  means 'Very dubious';  means 'Questionable';  means 'Possible';  means 'Probable';  means 'Likely';  means 'Most Likely' or *Unattested;  means 'Attested';  means 'Obvious' - only used for close matches within the same language or dialect, at linkable periods.