Cracking the Code: Tips for Icelandic Feminine Nouns

Feminine nouns (kvenkyn) in Icelandic can feel unpredictable, but they actually fall into three distinct "personality types" based on their plural endings: -ir, -ar, and -ur.

Here is a breakdown of the patterns and tips to help you remember them.

Group 1: The Reliable Ones (Kvk 1)

Plural Ending: -ir Example: Mynd (Picture)

This is the most straightforward group. These nouns usually don't change their vowel sounds; they just add endings.

The Pattern:

Singular: The word usually stays the same in Nom/Acc (Mynd), adds -ar in Genitive.

Plural: Adds -ir (Myndir).

Case	Singular (Et.)	Plural (Ft.)
Nf.	Mynd	Myndir
Þf.	Mynd	Myndir
Þgf.	Mynd	Myndum
Ef.	Myndar	Mynda

Common Words in this group: Sveit (countryside), leið (way), búð (shop), gjöf (gift).

Case	Singular (Et.)	Plural (Ft.)
Nf.	Sveit	Sveitir
Þf.	Sveit	Sveitir
Þgf.	Sveit	Sveitum
Ef.	Sveitar	Sveita

Case	Singular (Et.)	Plural (Ft.)
Nf.	Leið	Leiðir
Þf.	Leið	Leiðir
Þgf.	Leið	Leiðum
Ef.	Leiðar	Leiða

Case	Singular (Et.)	Plural (Ft.)
Nf.	Búð	Búðir
Þf.	Búð	Búðir
Þgf.	Búð	Búðum
Ef.	Búðar	Búða

Case	Singular (Et.)	Plural (Ft.)
Nf.	Gjöf	Gjafir
Þf.	Gjöf	Gjafir
Þgf.	Gjöf	Gjöfum
Ef.	Gjafar	Gjafa

Group 2: The "-ing" & "-ar" Club (Kvk 2)

Plural Ending: -ar Examples: Sneið, Skel, Setning, Helgi

This group is very common. It contains two specific types of words that are easy to spot:

Tip 1: The "-ing" Rule

If a feminine noun ends in -ing (like Setning, Rigning, Bygging), it always goes in this group.

Singular: Ends in -u for Acc/Dat/Gen (Setningu, Setningu, Setningar).
Plural: Ends in -ar (Setningar).

Memory Hook: If it's an "action" noun ending in -ing, give it a 'u' in the singular!

Case	Singular (Et.)	Plural (Ft.)
Nf.	Setning	Setningar
Þf.	Setningu	Setningar
Þgf.	Setningu	Setningum
Ef.	Setningar	Setninga

Tip 2: The Weak Feminine (-i)

Some feminine nouns end in -i in the singular, like Helgi (weekend) or Ermi (sleeve).

The Trick: These are "weak" nouns. The -i changes to -a in every other singular case.

Nf: Helgi
Þf/Þg/Ef: Helga

Plural: They take -ar (Helgar).

Case	Singular (Et.)	Plural (Ft.)
Nf.	Helgi	Helgar
Þf.	Helgu	Helgar
Þgf.	Helgu	Helgum
Ef.	Helga	Helga

Tip 3: The "J" Insert (J-innskot)

Some short words ending in 'l' or 'y', like Skel (shell) or Ey (island), need a helping consonant. They insert a j before the 'a' or 'u' endings.

Skel → Skeljar (plural).

Case	Singular (Et.)	Plural (Ft.)
Nf.	Skel	Skeljar
Þf.	Skel	Skeljar
Þgf.	Skel	Skeljum
Ef.	Skeljar	Skelja

Group 3: The Shapeshifters (Kvk 3)

Plural Ending: -ur Examples: Bók, Tönn, Kind

This group contains many very common everyday objects. They are tricky because they often undergo Vowel Shifts (B-víxl) in the plural.

The "Book" Pattern (ó → æ)

Words with ó usually shift to æ in the plural.

Bók (Book) → Bækur (Books)

Case	Singular (Et.)	Plural (Ft.)
Nf.	Bók	Bækur
Þf.	Bók	Bækur
Þgf.	Bók	Bókum
Ef.	Bókar	Bóka

Rót (Root) → Rætur (Roots)

Case	Singular (Et.)	Plural (Ft.)
Nf.	Rót	Rætur
Þf.	Rót	Rætur
Þgf.	Rót	Rótum
Ef.	Rótar	Róta

Brók (Pants) → Brækur.

Case	Singular (Et.)	Plural (Ft.)
Nf.	Brók	Brækur
Þf.	Brók	Brækur
Þgf.	Brók	Brókum
Ef.	Brókar	Bróka

The "Tooth" Pattern (ö → e)

Words with ö usually shift to e in the plural.

Tönn (Tooth) → Tennur (Teeth)

Case	Singular (Et.)	Plural (Ft.)
Nf.	Tönn	Tennur
Þf.	Tönn	Tennur
Þgf.	Tönn	Tönnum
Ef.	Tannar	Tanna

Önd (Duck) → Endur (Ducks)

Case	Singular (Et.)	Plural (Ft.)
Nf.	Önd	Endur
Þf.	Önd	Endur
Þgf.	Önd	Öndum
Ef.	Andar	Anda

Stöng (Pole) → Stengur (Poles).

Case	Singular (Et.)	Plural (Ft.)
Nf.	Stöng	Stengur
Þf.	Stöng	Stengur
Þgf.	Stöng	Stöngum
Ef.	Stangar	Stanga

Note on "Kind": Kind (Sheep) is in this group but is regular. It just becomes Kindur in the plural without a vowel shift.

Case	Singular (Et.)	Plural (Ft.)
Nf.	Kind	Kindur
Þf.	Kind	Kindur
Þgf.	Kind	Kindum
Ef.	Kindar	Kinda

The Exceptions

Some important words refuse to follow the rules above. Here are the ones listed in your summary:

Family Terms:

Móðir (Mother) → Mæður (Mothers) (Shift: ó → æ).

Case	Singular (Et.)	Plural (Ft.)
Nf.	Móðir	Mæður
Þf.	Móður	Mæður
Þgf.	Móður	Mæðrum
Ef.	Móður	Mæðra

Systir (Sister) → Systur (Sisters).

Case	Singular (Et.)	Plural (Ft.)
Nf.	Systir	Systur
Þf.	Systur	Systur
Þgf.	Systur	Systrum
Ef.	Systur	Systra

Short Words:

Á (River) → Ár

Case	Singular (Et.)	Plural (Ft.)
Nf.	Á	Ár
Þf.	Á	Ár
Þgf.	Á	Ám
Ef.	Ár	Á

Tá (Toe) → Tær (Shift: á → æ).

Case	Singular (Et.)	Plural (Ft.)
Nf.	Tá	Tær
Þf.	Tá	Tær
Þgf.	Tá	Tám
Ef.	Tár	Táa

Nótt (Night) → Nætur (Nights).

Case	Singular (Et.)	Plural (Ft.)
Nf.	Nótt	Nætur
Þf.	Nótt	Nætur
Þgf.	Nótt	Nóttum
Ef.	Nætur	Nótta

Mús (Mouse) → Mýs (Mice) (Shift: ú → ý).

Case	Singular (Et.)	Plural (Ft.)
Nf.	Mús	Mýs
Þf.	Mús	Mýs
Þgf.	Mús	Músum
Ef.	Músar	Músa

Summary Table

If the word looks like...	It's probably...	Plural ending
Ends in -ing	Group II	-ar
Ends in -i	Group II (Weak)	-ar
Has ó or ö inside	Group III (Shift)	-ur
Short, simple word	Group I	-ir

The Tricky "-i" and "-a" Endings (Don't Get Fooled!)

While studying feminine nouns, you will run into many words that end in -i or -a. Be careful, because gender can be deceptive here!

1. The "-i" Ending: Three Different Personalities

Not all words ending in -i behave the same way. You need to know if the word is a "Strong Feminine," a "Weak Feminine," or not feminine at all!

The "Strong" Feminine (Standard): Words like Helgi (weekend) are standard. They end in -i in the singular and change to -ar in the plural (Helgi → Helgar).

The "Abstract" Weak Feminine (No Plural): There is a specific group of feminine words ending in -i that represent abstract concepts or feelings. These words do not have a plural form (engin ft.).

Example: Veiki (sickness), elli (old age), gleði (joy), heppni (luck), kæti (joyfulness), leti (laziness), reiði (anger), speki (wisdom), ævi (lifetime).

The Imposters (Masculine & Neuter): Don't assume every word ending in -i is feminine!

Weak Masculine (Veik kk): Penni (Pen). It looks similar, but the plural is Pennar.

Case	Singular (Et.)	Plural (Ft.)
Nf.	Penni	Pennar
Þf.	Penna	Penna
Þgf.	Penna	Pennum
Ef.	Penna	Penna

Strong Neuter (Sterk hk): Dæmi (Example). The plural is exactly the same as the singular (Dæmi → Dæmi).

Case	Singular (Et.)	Plural (Ft.)
Nf.	Dæmi	Dæmi
Þf.	Dæmi	Dæmi
Þgf.	Dæmi	Dæmum
Ef.	Dæmis	Dæma

2. The "-a" Trap: Weak Neuter Nouns

Usually, if a word ends in -a, it is feminine (like Kona or Tunga). However, there is a specific list of Weak Neuter words (Veik hvorugkynsorð) that also end in -a.

Do not decline these like feminine nouns! This group includes many body parts and loan words:

Body Parts: Auga (eye), eyra (ear), lunga (lung), nýra (kidney), milta (spleen), hjarta (heart).