-uus

From Proto-Finnic *-uc. The declension has been massively reworked by analogy:

• The oblique plural forms originally declined like those of the käsi type, but were replaced by plurals in -ks- from the vastaus-type declension, formed on the analogy of the suffix -s.
  • Words that had acquired a nominal sense early on have crossed over entirely to the vastaus declension: e.g. sisarus (“sibling”), originally a semantic extension from *sisarus > sisaruus (“siblinghood”); vanhus (“old person”), originally a semantic extension from *vanhus > vanhuus (“oldness”).
• The long vowel appearing after consonants originates from a contraction *-ude- > *-ue- > -uu- in the genitive singular and nominative plural of bisyllabic stems, in which the third-syllable unstressed e was assimilated. This was generalized to other case forms of such words as well.
• In trisyllabic stems such as korkea → korkeus, rakas → rakkaus, the suffix would in all inflected forms gain secondary stress, preventing the loss of *-d-. From here *-d- was then reintroduced in the gen. sg. and nom. pl. of bisyllabic stems.
• Root-final consonants in trisyllabic stems were by contrast often lost (e.g. *korkeduden > korkeuden, *rakkahuden > rakkauden), leading to the regular retention of short -u- especially after vowels.
  • The rare exceptions to this such as sisar → sisaruus have however also acquired the long-vowel allomorph.

• IPA^(key): /ˈuːs/, [ˈuːs̠]

-uus (front vowel harmony variant -yys)

1. Forms nouns from adjectives, expressing a quality.

   -uus

   punainen (“red”) → punaisuus (“redness”)

   nerokas (“ingenious”) → nerokkuus (“ingenuity”)

   -yys

   pyhä (“holy”) → pyhyys (“holiness”)

   pitkä (“long”) → pituus (“length”) *not pitkyys

   -us

   hauras (“brittle”) → hauraus (“brittleness”)

   kaunis (“beautiful”) → kauneus (“beauty”)

   komea (“handsome”) → komeus (“handsomeness”)

   -ys

   leveä (“wide”) → leveys (“width”)

As a main rule, the suffix is added to the stem of the adjective, replacing any final vowel:

• kova (“hard”) → kovuus (“hardness”)
• kylmä (“cold”) → kylmyys (“coldness”)
• paksu (“thick”) → paksuus (“thickness”)
• suuri (“big”) → suuruus (“size”)
• sinise- (“blue”) → sinisyys (“blueness”)

The stem usually remains in the strong grade, but some exceptions remain as evidence of the original short vowel. In particular, all derivatives based on comparatives show the weak grade, e.g. alempi (“lower”) → *alemmus > alemmuus (“lowerness”), rather than ˣalempuus.

As noted above, the suffix additionally appears shortened to -us whenever it is preceded by a second vowel. Note that this includes contracted long vowels, as in *harmaɣa > harmaa (“gray”) → harmaus (“grayness”). Derivatives from adjectives ending in -is may in some cases show an unexpected alternation to -e-, as in the above-seen kauneus in place of expected ˣkaunius.

Some exceptions to this overall scheme occur, e.g. äiti (“mother”) → äitiys (“motherhood”), in place of expected ˣäityys. Very rarely, both allomorphs may even occur in parallel, e.g. lapsi (“child”) → lapsuus (“childhood; period of life”), yet lapseus (“childhood; state of being a child”).

• Hakulinen, Lauri. 1941–2000. Suomen kielen rakenne ja kehitys ('The Structure and Development of the Finnish Language'). Helsinki: Otava/Helsingin yliopisto.

• suu

• -vus

From the Proto-Indo-European perfect active participle *-wós.

• (Classical) IPA^(key): /u.us/, [ʊ.ʊs] (stressed on the antepenult)

-uus

1. forms adjectives on verbal stems

   contiguus, succiduus, vacuus

• Originally forming the perfect active participle, as in ambiguus (“having wandered”), mortuus (“having died”), vacuus (“having been empty”).
• The form -vus is used after vowels, l, and r, and -uus after all other other consonants, with the exception of qu. In this last case, the form -us is used.

First/second declension.