Magnetic ($chi$), transport ($rho$) and heat capacity ($C_m$)properties of CeIrSi are investigated to elucidate the effect of geometric frustration in this compound with trillium type structure because, notwithstanding its robust effective moment, $mu_{rm eff}approx 2.46mu_B$, this Ce-lattice compound does not undergo a magnetic transition. In spite of that it shows broad $C_m(T)/T$ and $chi(T)$ maxima centered at $T_{max}approx 1.5$,K, while a $rho propto T^2$ thermal dependence, characteristic of electronic spin coherent fluctuations, is observed below $T_{coh} approx 2.5$,K. Magnetic field does not affect significantly the position of the mentioned maxima up to $approx 1$,T, though $chi(T)$ shows an incipient structure that completely vanishes at $mu_0 H approx 1$,T. Concerning the $rho propto T^2$ dependence, it is practically not affected by magnetic field up to $mu_0 H = 9$,T, with the residual resistivity $rho_0(H)$ slightly decreasing and $T_{coh}(H)$ increasing. These results are compared with the physical properties observed in other frustrated intermetallic compounds