The Collaborative International Dictionary of English v.0.48:
Insitiency \In*si"ti*en*cy\, n. [Pref. in- not + L. sitiens, p. pr. of sitire to be thirsty, fr. sitis thirst.] Freedom from thirst. [Obs.] [1913 Webster] The insitiency of a camel for traveling in deserts. --Grew. [1913 Webster]