Personal luck and protective spirit that follows a family line.

In Old Norse belief, hamingja denotes the luck and vital force bound to an individual or an entire kin group. It can pass between generations and is strengthened by honourable deeds.

A powerful hamingja protects its bearer in battle and brings success to undertakings. If a man loses his hamingja it may transfer to a worthier kinsman.

Attestations

Zoëga, A Concise Dictionary of Old Icelandic (1910)
Foundational lexical reference for the term.