What does sīquis mean in Latin?

sīquis, a pronoun, means “if any; if anyone”.

How do you pronounce sīquis?

In classical Latin, [ˈsiː.kʷɪs]; in ecclesiastical (church) Latin, [ˈsiː.kʷis].

pronoun

Classical[ˈsiː.kʷɪs]Ecclesiastical[ˈsiː.kʷis]

if any
if anyone
siquis·hic·sederit legat·hoc·ante·omnia siqui·futuere·uolet atticen quaerat a·xvi·before 79 AD, C.I.L 4.1751 (graffiti inscribed outside of the Marina Gate in Pompeii)

singular
form	masculine	feminine	neuter
nominative	sīquis sīquī, sīquei	sīqua sīquae	sīquid
dative	sīcui sīquoi, quoei, sīquoiī, quoiei	sīcui sīquoi, quoei, sīquoiī, quoiei	sīcui sīquoi, quoei, sīquoiī, quoiei
accusative	sīquem	sīquam	sīquid
ablative	sīquō sīquī	sīquā sīquī	sīquō sīquī

plural
form	masculine	feminine	neuter
nominative	sīquī sīquei, sīquēs	sīquae sīquēs	sīqua sīquae
dative	sīquibus sīquīs, sīqueis	sīquibus sīquīs, sīqueis	sīquibus sīquīs, sīqueis
accusative	sīquōs sīquēs	sīquās sīquēs	sīqua sīquae
ablative	sīquibus sīquīs, sīqueis	sīquibus sīquīs, sīqueis	sīquibus sīquīs, sīqueis

sī-quis or sī-qui, sīqua, sīquid or sīquod, or separately, sī quis, etc.,

I. indef. pron. (v. Zumpt, Gr. § 740), if any, if any one: si quis recte Tractaret, Ter. Heaut. 1, 1, 100: si qui (filius) natus esset, Cic. Clu. 12, 33: si qua tui Corydonis habet te cura, Verg. E. 7, 40.—Adverb.: si qui and si qua, if in any way, if by any means: si qui, Liv. 3, 64 fin.; Plaut. Trin. 1, 2, 83: si qua, id. Cist. 1, 3, 35; Verg. A. 1, 18; Hor. C. 3, 14, 19: si quo, if any whither, Cic. Att. 8, 2, 1; also, if for any purpose, Liv. 37, 28: si quid, if at all, Verg. A. 5, 688; cf. 2. quis.

From sī- + quis.