ず

The hiragana character す (su) with a dakuten (゛).

• IPA^(key): [d͡zɨᵝ], [zɨᵝ]

ず • (zu) 

1. The hiragana syllable ず (zu). Its equivalent in katakana is ズ (zu).

From Old Japanese. Generally considered to be a combination of negation suffix ぬ (-nu), in its 連(れん)用(よう)形(けい) (ren'yōkei, “continuative or stem form”) of に (ni), + verb す (su, “to do”).^[1][2]

/nisu/ → */nzu/ → /zu/

Appears both as zu and as the older nisu form in the Man'yōshū poetry anthology.

• IPA^(key): [d͡zɨ]

• In the modern Tokyo dialect, when ず (-zu) attaches to the 未(み)然(ぜん)形(けい) (mizenkei, “irrealis or incomplete form”) of a verb, the resulting accent usually follows the accent of the base verb, but exceptions are to be observed:

• When attaching to a 平(へい)板(ばん)式(しき) (heiban-shiki) verb, the result is also 平(へい)板(ばん)式(しき) (heiban-shiki):

言(い)う (iu): いう [iu] (Heiban – [0]) → いわず [iwazu] (Heiban – [0])

寝(ね)る (neru): ねる [neru] (Heiban – [0]) → ねず [nezu] (Heiban – [0])

• When attaching to a 起(き)伏(ふく)式(しき) (kifuku-shiki) verb, the result is also 起(き)伏(ふく)式(しき) (kifuku-shiki), with the アクセント核(かく) (akusento-kaku, “accent kernel”) usually falling on the mora before ず (-zu):

書(か)く (kaku): か​く [kaꜜku] (Atamadaka – [1]) → かか​ず [kakaꜜzu] (Nakadaka)

出(で)来(き)る (dekiru): でき​る [dekiꜜru] (Nakadaka) → でき​ず [dekiꜜzu] (Nakadaka)

• For some accented ず (-zu) forms, the アクセント核(かく) (akusento-kaku, “accent kernel”) falls on the mora before the mora before the ず (-zu). This is in particular the case for fossilized (lexicalized) adverbials, as opposed to spontaneous suffixation. These exceptional accents are more traditional. In some cases, both accents exist with the exceptional, traditional accent being more strongly associated with the fossilized, adverbial meaning and the regular, modern accent being more strongly associated with the predictable verbal meaning.

  Examples of exceptional accents include 非(あら)ず (arazu), 可(べ)からず (bekarazu), 思(おも)わず (omowazu), and 問(と)わず (towazu).

• As with せ​ぬ (senu) and せ​よ (seyo), せ​ず (sezu) is accented even though する (suru) is not.
• Some lexical items such as 恥(はじ)知(し)らず (hajishirazu) may appear to be exceptional when they are not; they get their accent from compounding:

  はじ​ [hajiꜜ] (Odaka) + しらず [shirazu] (Heiban – [0]) → はじし​らず [hajishiꜜrazu] (Nakadaka)

ず • (-zu) 

1. not doing

   何(なに)も知(し)らず

   nani mo shirazu

   not knowing anything

Just like the older negation suffix ぬ (-nu) and the modern negation suffix ない (-nai), ず (-zu) comes after the 未(み)然(ぜん)形(けい) (mizenkei, “irrealis or incomplete form”) of a verb.

The suffix ず (-zu) is more formal than the everyday negation suffix ない (-nai).

The kanji spelling 不 attaches to verbs as a prefix in kanbun style, forming jukujikun readings such as 不知(しらず) (shirazu) or 不悪(あしからず) (ashikarazu).

• ずに (-zu ni, “without”)