Slackness
Negligence, Not using due diligence (Noun).
Holt
Woods. C.f. Chaucer: “Inspired hath in every holt and heath” (The General Prologue to The Canterbury Tales).
Array
Arrangement, Formation, Assemblage (Noun). E.g. ‘an array of soldiers’.
Errand
Message or Mission. From Old English ærende.
Truce
Armistice, Ceasefire (Noun).
Spear-rush
A battle, or a rush of soldiers with spears. This is a kenning, a kind of metaphorical compound frequently used in the Old English, Old Norse, and later Icelandic poetry.
Boastfully
Alongside the modern English meaning ‘Proudly’, it may also mean threateningly, because the Old English ‘on beot’ meant threatening.
Hearth-band
Personal followers. From Old English ‘Heorðwerod’.
Stead
Place, as in ‘Hampstead’ or ‘Homestead’.
Battlefield
The original Old English word was Wælstowe, meaning ‘corpse-place’.
Board
Shield. From Old English Bord, one of several words used in the poem to refer to a shield.
Fold
Earth. From Old English Folde.
Flane-flight
Flight of an arrow. From Old English Flanes Flyht.
Ash-army
In Old English, synecdoche was a regular rhetoric. Thus, ‘ash’ here refers to spears made of ash-wood, and ‘ash-army’ is the militia that used such weapons.
Linden
Shields made of linden wood; another synecdoche.
Methel-stead
Counsel-chamber. Literally, ‘speaking place’. Example of a kenning.
Moot
Meeting, Assembly. From Old English ‘Gemot’.
Old father
Grandfather. From Old English Ealda Fæder.
Alderman
A nobleman. From Old English Ealdorman.
Hale
Healthy. Used in Modern English as the idiomatic ‘hale and hearty’.
Humbled
Crushed in a battlefield. From Old English Hynde.