quis

From Proto-Italic *kʷis, from Proto-Indo-European *kʷís. See there for cognates.

Pronunciation

(Classical Latin) IPA^(key): /kʷis/, [kʷɪs̠]
(modern Italianate Ecclesiastical) IPA^(key): /kwis/, [kwis]

Pronoun

quis or quī (feminine quae or qua or quis, neuter quid); relative/interrogative pronoun (with m optionally → n in compounds)

(interrogative pronoun)
1. (in the masculine singular, not agreeing with any other word) who [ quotations ▼]
  Quis custōdiet ipsōs custōdēs? ― <But> who will watch the watchmen themselves?
2. (in the neuter singular, not agreeing with any other word) what [ quotations ▼]
  Quid accidit? ― What happened?
3. (agreeing in gender with a noun in a copular sentence) what [ quotations ▼]
4. (as predicate agreeing in gender and number with subject) who
  Quis es? ― Who are you? (with the default emphasis on you)
  
  Quis es tū? ― Who are you? (with the marked emphasis on are)
  
  Quī sumus? ― Who are we?
5. (in the neuter quid) why, what for [ quotations ▼]
(indefinite pronoun, alone and after si, nisi, num, ne) someone, something, anyone, anything; any [ quotations ▼]

Usage notes

As a question word, quis usually occupies the first position in a clause, regardless of its syntactic function (although it may be preceded by a connector or a pragmatically fronted constituent).^[2]
In a question that does not contain a copular verb, the interrogative pronoun is usually masculine singular (quis) when asking for the identity of some person(s) and neuter singular (quid) when asking for the identity of some thing. In all periods of Latin, the masculine forms of quis can be used as a generic interrogative pronoun with a scope including both male and female beings despite its masculine grammatical gender (compare the generic sense of the masculine noun homo (“man, human being”)).
In questions that contain a form of the copula esse and a noun in the nominative case in addition to a nominative form of quis, the form of quis may match the gender and number of the noun by attraction. In this context, any form of quis can mean either "who" or "what": the meaning depends on the sense of the noun, while the form and grammatical gender is derived from agreement with the grammatical gender of the noun. But it is also possible alternatively for the neuter singular form quid to be used as a predicative pronoun with the sense "what" in a question with a masculine, feminine or plural subject, with no agreement in gender or number between the subject and the predicate. According to Lebreton, agreement is rarer than the use of the non-agreeing neuter interrogative pronoun, but neither is exceptional.^[3] It is not always simple in copular questions to determine whether a form of quis is acting as an interrogative pronominal subject, an interrogative pronominal predicate, or an interrogative adjective (see also quī), since the same grammatical case is used for all of these functions, and as mentioned above, Latin regularly places an interrogative word first regardless of its syntactic function in a clause.

Declension

Interrogative and indefinite pronoun.

Case / Gender	Masculine	Feminine	Neuter	Masculine	Feminine	Neuter
Number	Singular			Plural
Nominative	quis quī¹	quae qua² quis	quid	quī¹	quae	quae qua²
Genitive	cuius¹			quōrum	quārum	quōrum
Dative	cui¹			quibus quīs¹
Accusative	quem	quam quem	quid	quōs	quās	quae qua²
Ablative	quō quī	quā quī	quō quī	quibus quīs¹

¹In Republican Latin or earlier, alternative spellings could be found for the following forms of quī/quis and its compounds: the masculine nominative singular or plural quī (old spelling quei), the genitive singular cuius (old spelling quoius), the dative singular cui (old spelling quoi or quoiei), the dative/ablative plural quīs (old spelling queis).
²When used as an indefinite word (pronoun or adjective), the feminine nominative singular and neuter nominative/accusative plural is usually qua (with short ă) instead of quae. Indefinite quă is generally only found directly after sī, nisi, num, or nē and may be considered to be either enclitic to the preceding word or (in Priscian's view) forming a compound with it; accordingly, sīqua, numqua, and nēqua are sometimes written together (as also are the masculines sīquis, numquis, and nēquis). The form quă is never used for the feminine plural, nor for any form of the relative pronoun or of the interrogative pronoun or adjective.

An archaic form of the nominative plural is quēs (found on the Senatus consultum de Bacchanalibus).
In the early Latin of Ennius, Pacuvius, and Plautus,^[4] the form quis is sometimes used as a feminine nominative singular predicative interrogative pronoun or a feminine singular interrogative adjective, not only including women in a generic sense, but even in reference to a specific woman (see Citations:quis). But use of the form quis as a specifically feminine pronoun is rare in later time periods. The feminine nominative singular form quae is also attested in reference to a woman or in agreement with a feminine noun (see Citations:quae), but it can be difficult to determine whether feminine interrogative quae is a form of the pronoun quis (“who”), or a form of the interrogative adjective quī (“which”) (which can be used substantivally).

Adjective

quis or quī (feminine quae, neuter quod); relative/interrogative pronoun

(alternative nominative singular form of adjectival interrogative pronoun quī) which [ quotations ▼]

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