Lewis & Short

iste, a, ud, gen. istīus (the poets often make the penult of the gen. short: istĭus, Verg. A. 12, 648: istius, dissyl., Plaut. Most. 3, 2, 59; Ter. Phorm. 5, 8, 76 al.
An old form of the gen. isti, with modi, Cato ap. Prisc. p. 694 P.; Plaut. Truc. 5, 38.
With affixed ce: istisce, Plaut. Rud. 3, 4, 40; and in interrogations, cine: istoscine patrem aequum’st mores liberis largirier? id. As. 5, 2, 82.
Dat. isto, App. M. 5, 31, p. 172 fin. al.; dat. f. istae, Plaut. Truc. 5, 38.
Shortened form, ste, sta, stoc, etc.; v. Non. p. 476; Lachm. ad Lucr. 3, 954), pron. demonstr. [compounded of two pronom. stems, i- (cf. is) and to-; Sanscr. -ta; cf. tam, tum], this, that (man, woman, thing), called the demonstr. of the second person, since it is especially used in reference to persons and things connected in place, relation, or thought, with the person addressed.

  1. I. In gen.
    1. A. That (person or thing) near to you (in place or thought), that of yours, that of which you speak or with which you are connected: si ista nobis cogitatio de triumpho injecta non esset, Cic. Fam. 7, 3, 2: istae minae, those threats of yours, Liv. 4, 5: de istis rebus exspecto tuas litteras, those affairs of yours, Cic. Att. 2, 5, 2: quid quod adventu tuo ista subsellia vacuefacta sunt, those seats where you are sitting, id. Cat. 1, 7, 16; id. de Sen. 17, 59: quae est ista praetura? that prætorship of yours, id. Verr. 2, 2, 18, § 46: quaevis mallem fuisset (causa), quam ista quam dicis, id. de Or. 2, 4, 15.
      1. 2. So with pronom. of the second person: cum enim tuus iste Stoicus sapiens dixerit, Cic. Ac. 2, 38, 119: quid iste tuus vates donat? Ov. Am. 1, 8, 57: iste vester (sapiens), Cic. Ac. 2, 33, 105: quae tua est ista vita, id. Cat. 1, 7, 16.
    2. B. With a general reference, that, this, the very, that particular (person or thing), he, she, it.
      1. 1. Alone, as pron.: illae quae cum isto cubant, Plaut. Mil. 1, 1, 65: credis quod iste dicit, Ter. Eun. 4, 4, 44: haec quae ista elementa videantur, Cic. de Or. 1, 35, 163.
      2. 2. With substt.: erat enim ab isto Aristotele, a cujus inventis, etc., Cic. de Or. 2, 38, 160: ista divina studia, id. de Sen. 7, 24: ut jam ne istius quidem rei culpam sustineam, id. Att. 7, 3, 1: nec enim ab isto officio abduci debui, id. Lael. 2, 8.
      3. 3. With other pronouns: istius ipsius in dicendo facultatis, Cic. de Or. 2, 29, 128: transeat idem iste sapiens ad rem publicam tuendam. id. Tusc. 5, 25, 72: in eodem isto Aegyptio regno vitā privatus, id. Rab. Post. 9, 23.
      4. 4. With the rel.: necesse est eam, quae suum corpus prodixerit turpissimae cupiditati, timere permultos. Quos istos? etc., Auct. Her. 4, 16, 23.
  2. II. In partic.
    1. A. Like is in the sense of tantus and talis, such, of such a kind: quare cum ista sis auctoritate, etc., Cic. Mur. 6, 13: servi mei, si me isto pacto metuerent, ut te metuunt omnes, etc., id. Cat. 1, 7, 17: homines ista auctoritate praediti, qua vos estis, id. Rosc. Am. 53, 154: animo isto esse, Nep. Eum. 11, 4: egon, quidquam cum istis factis tibi respondeam, Ter. Eun. 1, 2, 73.
    2. B. It freq. implies scorn or contempt: non erit ista amicitia, sed mercatura, Cic. N. D. 1, 44, 122; id. Cat. 2, 7: iste otii et pacis hostis, id. Dom. 5, 12: animi est ista mollities, non virtus, inopiam paulisper ferre non posse, Caes. B. G. 7, 77: hic vestis cum isto squalore permutandus, Curt. 4, 1, 22; 3, 2, 16: tuus iste frater, Petr. 9: o isti, an urgent form of address, Arn. 1, 23, 36 et saep.
    3. C. In the abl.: isto, for this reason, therefore: isto tu’s pauper, quom nimis sancte piu’s, Plaut. Rud. 4, 7, 8.