Instantia, huius instantiæ, f. g. Plini. iun. Earnest and continual diligeuce: earnest vebemencie.Instantia orationis. Pli. iu. Earnest behemency of an oratiõ.Peccata condicere necessitati cuidam & instantiæ. Gel. To attribute the offences of men to a certaine fatal necessitie and constraint that vrgeth them.
Lewis and Short: Latin dictionary
instantĭa, ae, f. [insto]. I.Lit., a being near or close upon, hence presence: futura quorum consequenti tempore vera erit instantia, ea vera dicimus, Cic. Fat. 12, 27 B. and K.: infestus dicitur ab instantia atque imminentia fraudis, the immediate and threatening character of the injury, Nigid. ap. Gell. 9, 12, 6.—II.Trop., steadiness, constancy, perseverance; force, vehemence in speaking; earnestness in supplication, importunity, urgency (post-Aug.): quid est enim, quod haec instantia non possit efficere?Plin. Ep. 3, 5, 18: oratio maxime vi, amaritudine, instantiā placet, id. ib. 5, 8, 10; opp. tarditas, Sol. 2, 46: repetendi debiti instantia, Dig. 32, 1, 32: sed instantia Byrrhaenae perfecit, ut vellet, App. M. 2, p. 123, 38: pertinaci negare instantia, Amm. 28, 1, 19.