The story
- Old Norse · derived fromfúll“foul”
- Old Norse · derived fromfúlmár
- Icelandic · borrowed fromfúlmár
- English todayfulmar
From Icelandic fúlmár, from Old Norse fúlmár, from Old Norse fúll (“foul”) + már (“gull, mew”) (see English mew), evidently in reference to the foul-smelling vomit it ejects to deter predators.
Etymology from Wiktionary, CC BY-SA 4.0.