# -о
## Belarusian
### Pronunciation

* IPA: [o]

### Suffix

-о́ • (-ó)
* Stressed variant of -а (-a).

#### Derived terms
## Bulgarian
### Suffix

-о • (-o)
* Suffix added to adjectives to produce adverbs.
    ‎я́сен (jásen, “clear”) + ‎-о (-o) → ‎я́сно (jásno, “clearly”)

#### Derived terms
## Russian
### Alternative forms

* -е (-e) — after palatalized consonants, hushing consonants and ц

### Pronunciation

* -о: IPA: [ə]
* -о́: IPA: [ˈo]

### Suffix

-о or -о́ • (-o or -ó)
* Suffix added to adjectives to produce adverbs; highly productive
    ‎однозна́чный (odnoznáčnyj, “unambiguous”) + ‎-о (-o) → ‎однозна́чно (odnoznáčno, “unambiguously”)
    ‎бы́стрый (býstryj, “quick, fast”) + ‎-о (-o) → ‎бы́стро (býstro, “quickly”)
    ‎сме́лый (smélyj, “brave”) + ‎-о (-o) → ‎сме́ло (smélo, “bravely”)
    ‎го́рький (górʹkij, “bitter”) + ‎-о (-o) → ‎го́рько (górʹko, “bitterly”)
    ‎со́бственный (sóbstvennyj, “(one's) own”) + ‎-о (-o) → ‎со́бственно (sóbstvenno, “in fact, as a matter of fact”)
    ‎больно́й (bolʹnój, “sick, painful”) + ‎-о (-o) → ‎бо́льно (bólʹno, “painfully; extremely”)
    ‎глухо́й (gluxój, “deaf; dull, muffled”) + ‎-о (-o) → ‎глу́хо (glúxo, “deafly; dully, in a muffled manner”)
    ‎дорого́й (dorogój, “expensive, dear”) + ‎-о (-o) → ‎до́рого (dórogo, “expensively, dearly”)
    ‎ра́вный (rávnyj, “equal”) + ‎-о́ (-ó) → ‎равно́ (ravnó, “equally”)
    ‎смешно́й (smešnój, “funny, comic”) + ‎-о́ (-ó) → ‎смешно́ (smešnó, “in a funny manner, comically”)
    ‎у́мный (úmnyj, “clever, wise”) + ‎-о́ (-ó) → ‎умно́ (umnó, “cleverly, wisely”)
    ‎лёгкий (ljóxkij, “light; easy”) + ‎-о́ (-ó) → ‎легко́ (lexkó, “lightly; easily”)
    ‎хоро́ший (xoróšij, “good”) + ‎-о́ (-ó) → ‎хорошо́ (xorošó, “well”)
    ‎горя́чий (gorjáčij, “hot; hot-tempered”) + ‎-о́ (-ó) → ‎горячо́ (gorjačó, “hotly, warmly; passionately”)
    ‎да́вний (dávnij, “old, ancient, bygone”) + ‎-о́ (-ó) → ‎давно́ (davnó, “long ago”)

#### Usage notes

* The ending is most commonly unstressed even when the adjective is ending-stressed, but is sometimes stressed. Most of the time, whether the adverbial ending is unstressed or stressed follows the corresponding short neuter singular form of the adjective.
* This ending replaces -е (-e) when stressed.

#### See also

* -и (-i) (used to form adverbs from adjectives whose stem ends in -ск- or -ий-/-j-)

## Ukrainian
### Alternative forms

* -ьо (-ʹo) — with adjectives with a soft ending
* -е (-e) — with some adjectives, predominantly comparatives

### Pronunciation 1

* -о: IPA: [ ɔ]

#### Suffix

-о • (-o)
* Suffix added to adjectives to produce adverbs.
    ‎глибо́кий (hlybókyj, “deep”) + ‎-о (-o) → ‎гли́боко (hlýboko, “deeply”)
    ‎ти́хий (týxyj, “quiet”) + ‎-о (-o) → ‎ти́хо (týxo, “quietly”)
    ‎очеви́дний (očevýdnyj, “obvious”) + ‎-о (-o) → ‎очеви́дно (očevýdno, “obviously”)
    ‎прости́й (prostýj, “simple”) + ‎-о (-o) → ‎про́сто (prósto, “simply”)
* Suffix added to adjectives and past participles to form predicatives or impersonal forms without a gendered referent.
    Тут ти́хо. ― Tut týxo. ― It is quiet here.
    Це неможли́во. ― Ce nemožlývo. ― That is impossible.
    Зна́йдено нови́й вид! ― Znájdeno novýj vyd! ― New species found!

##### Usage notes

* The ending is almost always unstressed, even when the base adjective has its stress on the ending.

##### Derived terms
### Pronunciation 2

* IPA: [ ˈɔ]

#### Suffix

-о́ • (-ó) n sg
* vocative singular of -а́ (-á)