Old Norse/Grammar/Adjectives and Adverbs

Strong Adjective Declension

Singular				Plural
Case	Masculine	Neuter	Feminine	Masculine	Neuter	Feminine
Nominative	-r	-t	-(u-umlaut)	-ir	-(u-umlaut)	-ar
Genitive	-s	-s	-rar	-ra	-ra	-ra
Dative	-um	-u	-ri	-um	-um	-um
Accusative	-an	-t	-a	-a	-(u-umlaut)	-ar

Weak Adjective Declension

Singular				Plural
Case	Masculine	Neuter	Feminine	Masculine	Neuter	Feminine
Nominative	-i	-a	-a	-u	-u	-u
Genitive	-a	-a	-u	-u	-u	-u
Dative	-a	-a	-u	-um	-um	-um
Accusative	-a	-a	-u	-u	-u	-u

Note the weak declension here, neuter is always 'a.' Masculine is 'i' in the nominative, but 'a' elsewise. The plural is 'u' except the dative 'um' ending.