-uus

• -us (see the usage notes)

From Proto-Finnic *-uc. The declension has been massively reworked by analogy.^[1]

• IPA^(key): /-uːs/,

-uus (front vowel harmony variant -yys, linguistic notation -UUs)

1. Forms nouns from adjectives or other nouns, expressing a quality of being that which is described: -ness, -hood, -ity, -th, -ship

   ‎punainen (“red”) + ‎-uus → ‎punaisuus (“redness”)

   ‎nerokas (“ingenious”) + ‎-uus → ‎nerokkuus (“ingenuity”)

   ‎pyhä (“holy”) + ‎-yys → ‎pyhyys (“holiness”)

   ‎jyrkkä (“steep”) + ‎-yys → ‎jyrkkyys (“steepness”)

   ‎hauras (“brittle”) + ‎-us → ‎hauraus (“brittleness”)

   ‎kaunis (“beautiful”) + ‎-us → ‎kauneus (“beauty”)

   ‎komea (“handsome”) + ‎-us → ‎komeus (“handsomeness”)

   ‎leveä (“wide”) + ‎-ys → ‎leveys (“width”)

   ‎nerokas (“ingenious”) + ‎-uus → ‎nerokkuus (“ingenuity”)

   ‎mestari (“champion”) + ‎-uus → ‎mestaruus (“championship”)

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

• ‎kova (“hard”) + ‎-uus → ‎kovuus (“hardness”)
• ‎kylmä (“cold”) + ‎-uus → ‎kylmyys (“coldness”)
• ‎paksu (“thick”) + ‎-uus → ‎paksuus (“thickness”)
• ‎suuri (“big”) + ‎-uus → ‎suuruus (“size”)
• ‎sinise- (“blue”) + ‎-uus → ‎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 **alempuus.

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 **kaunius.

Some exceptions to this overall scheme occur, e.g. äiti (“mother”) → äitiys (“motherhood”), in place of expected **äityys. 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”).

• suu

From Proto-Finnic *-uc. Cognates include Finnish -uus and Estonian -us.

• (Ala-Laukaa) IPA^(key): /-uːs/,
• (Soikkola) IPA^(key): /-uːs/,

-uus (front vowel variant -yys)

1. Forms nouns from adjectives, expressing a quality; -ness

   ‎syvä (“deep”) + ‎-uus → ‎syvvyys (“depth”)

• The suffix is always appended to the oblique stem.
• When following a short stressed syllable, the long form -uus is used. In all other cases, the alternative form -us is used instead:

  ‎pitä- + ‎-uus → ‎pittuus

  ‎vanh- + ‎-uus → ‎vanhus

• Note that since the suffix -kas always carries secondary stress, the derivatives in -uus also always contain a long vowel:

  ‎voimakka- + ‎-uus → ‎voimakkuus

• V. I. Junus (1936) Iƶoran Keelen Grammatikka‎, Leningrad: Riikin Ucebno-pedagogiceskoi Izdateljstva, page 58

• -vus

Inherited from Proto-Italic *-wos, from Proto-Indo-European *-wós‚ from the perfect active participle suffix *-wōs.

• (Classical Latin) IPA^(key): /u.us/,
• (modern Italianate Ecclesiastical) IPA^(key): /u.us/, (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 adjective.