This is a companion to the post about compound words that I made earlier. Sometimes Icelandic words are often made of more than one stem/root words at once, along with suffixes, infixes (like a suffix or prefix but in the middle of words), et cetera. This means they’re compound words but not necessarily compounds that are comprised of whole words. Sometimes the reason for this is because they had to create a new word from existing ones to avoid borrowing words from other languages. This ends up looking like maybe they took half of one Icelandic word and put it together with another word, then added a common suffix to make it an adjective or noun. A nice, clear example of some of these things is here if you can read the Icelandic, and I’ll use this in my examples today because I can’t come up with something as clear as that.

orð – word
samsett orð – compound word
samsetning – compound (remember the -ing ending means you have to add -ar to make it plural, so “samsetningar – compounds”)
stofn – stem/root of a word
eignarfall – genitive case
tengi – connection
stafur – letter (as in letter of the alphabet)
hljóð – sound
forskeyti – prefix
viðskeyti – suffix

“Eignarfallssamsetning – genitive-compound”. This is what was taught in the post about genitive case. It’s when you take nouns and add them together to make a compound word by putting the beginning words into genitive case and the last word of the compound in nominative case.

“Stofnsamsetning – stem-compound”. This is when you take stems of words and put them together, without changing the beginning words into genitive case (you’re taking only the stems, not any of the endings). These are typically words that you can search for in the dictionary. Ex. “eldhús – kitchen” is from eldur – fire and hús – house, and you can search for the entire thing in the dictionary. They just took the stem of eldur, they didn’t change it into genitive form.

“Tengistafssamsetning – connecting-letter compound”, also called “tengihljóðssamsetning – connecting-sound compound” and “bandstafssamsetning – binding compound”. This is an extra letter or two added in-between two stems, words, etc. and these extra letters weren’t just added because of grammar rules (as is the case when changing the endings of words to genitive to form compound words). Binding letters are all vowels except for the letter s.
Ex. Eldiviður (firewood). The i isn’t part of eldur’s stem, and there’s no i added in any genitive form of it either. Similarly, i isn’t the beginning of viður. This is how you can tell that it’s not made by a grammar rule, and is thus a connecting-letter compound.

Derived (afleiddur) words can be words taken from older words and changed a little to mean new things like by having nouns turned into adjectives or by adding a prefix or suffix to an existing word. Every word has a stem. Some words also have a suffix tacked onto that stem, and can even have yet another suffix (or “ending”) added to the first one. “Kort (card)” is just a stem, but “hest-ur (horse)” has a stem and an ending while “leik-ar-i (actor)” is comprised of stem-infix-suffix, or if you’re used to reading things in Icelandic it’s called stem-suffix-ending. (I’m no grammar master, so I may be using the terms wrong.) Suffixes, infixes, endings, they all have declension patterns too although I won’t be posting those here. Here are just a few examples:

Prefix: ó (meaning the prefixes “un/im” in English)
ókurteis – uncourteous, impolite.
kurteis – courteous, polite.
óþolinmóður – impatient.
þólinmóður – patient.

Infix: -ast- (people also see -asti as a suffix though)
kærasti – male lover/fiance
I don’t think infixes necessarily mean anything that will make the meaning of the word clearer and they might not be reused often either. Many people break them up a little differently and just call them suffixes instead. Infixes all have declination patterns just like suffixes do.

Suffix: -laus (often meaning “-less/-free”, but as an adjective on its own it means “loose, free, vacant”)
sykurlaus – sugarless/sugarfree
sykur – sugar
eigandalaus – ownerless (ex. I heard this once when someone was asking about if a dog sitting around nearby was ownerless)
eigandi – owner

Suffixes: -ari and -andi are two similar ones. -ari often denotes a profession while -andi doesn’t. Both sometimes mean the suffix “er, or” in English, as in “employer – the one employing” versus “employee – the one being employed”. In other words, they’re suffixes that mean “a person who’s doing something”. I’m not sure how else to describe it, but hopefully the examples clear things up.
Examples: kennari (teacher), leikari (actor), sigurvegari (winner, conqueror), klippari (cutter, editor)
nemandi (student), gefandi (donor, giver), þýðandi (translator), neytandi (consumer), notandi (user)

There will be a more detailed post later on some of the affixes that have meanings.