In the Old English epic poem Beowulf, Unferth or Hunferth is a thegn (a retainer, servant) of the Danish lord Hrothgar. He appears five times in the poem — four times by the name 'Hunferð' (at lines 499, 530, 1165 and 1488) and once by the appellation "the son of Eclafes" (at line 980). The name Unferth does not appear in any Old English manuscript outside of the Nowell Codex, which contains Beowulf, and the meaning of the name is disputed. Several scholarly theories about Unferth have been proposed.

Unferth's name can be understood in a number of ways. A common reading, by Morton W. Bloomfield is to see it as un + frith, "mar peace": similarly, J. R. R. Tolkien considered the name to mean Unpeace/Quarrel, or perhaps 'Unfriend'. However, Searle's Onomasticon Anglo-Saxonicum lists several mentions of medieval historic personages, such as bishops and archbishops, named Hunfrith. Another reading, by Fred C. Robinson, is to see it as un + ferth, "no wit".

Other scholars, such as R. D. Fulk, have suggested that Unferth's name should not be associated with frið (peace) but with ferhð, which translates as “soul, spirit, mind, and life.” Fulk writes that it is difficult to assign significance to names in Beowulf because some of the characters involved are historical figures. However, Fulk argues that this can be done in the case of Unferth because the name Un-ferth is not known to appear in history, or in any manuscript other than the Nowell Codex. But the Chronicon Ex Chronicis, a 12th-century history of England, variously attributed to Florence of Worcester ("Florentii Wigorniensis") or to John of Worcester, mentions an 8th-century bishop of Winton whose name in Latin is given as "Hunfridus" and "Hunfertho".

The first element of the name, un, appears exclusively as hun in the sole manuscript of Beowulf, yet the alliterative metre of the poem shows conclusively that when the poem was composed the name began with a vowel. Fred C. Robinson suggested that this h- was a Celtic scribal habit, indicating that u had a vocalic function by adding an unpronounced, diacritic letter h. Fulk argued, however, that this use of the letter h does not appear anywhere else in the Beowulf manuscript, and Leonard Neidorf concluded that a scribe substituted the element Hun- for Un- simply because Hun- was familiar to him as a name element where Un- was not.

In Old English, un usually functions as a negative prefix. However, in certain contexts the meaning must be interpreted as 'abnormally', rather than 'not' (cf. German Untiefe, un-depth, which may mean either an excessive or an insufficient depth, or Old English unhar, "very old"). This use of un could add new possibilities to the meaning of the name Unferth. Despite the vast amount of research that has gone into the etymology of Unferth's name, there can be no easy consensus about its meaning.

Unferth appears a total of five times in Beowulf.

Unferth first appears at line 499:

Hunferð maþelode, Ecglafes bearn,
þe æt fotum sæt frean Scyldinga.