Display omitted •The effect of various defects and temperature on thermal conductivity of silicene is studied using NEMD.•Only 5% of carbon doping are found to reduce the thermal conductivity of pure silicene by ~ 71%.•Reduction of thermal conductivity is more pronounced with the increased vacancy than carbon.•PDOS reveals the high-frequency regime exhibit a redshift for carbon-doped silicene.•Both pristine and carbon-doped silicene exhibit isotropic thermal conductivity behavior. Silicene has recently grabbed tremendous attention in the scientific community owing to its superb electronic and thermal properties and the promise of high-efficiency thermoelectric operations. Notwithstanding rigorous analyses of its electronic properties, little attention has been paid so far to explore and tailor the thermal transport characteristics of silicene. This study employed optimized Tersoff potential to extensively investigate the thermal conductivity (TC) of pristine and defective silicene using non-equilibrium molecular dynamics (NEMD) simulations. We analyzed theinfluence of temperature variation, percentage of carbon doping, andmonovacancy concentration on the phonon TC along both armchair and zigzag directions and elucidated the underlying mechanisms that modulate these effects. The simulation results reveal excellent isotropic behavior of the material in the considered temperature regime. Our predicted room-temperature TC of pristine silicene of ~ 20 W/m.K shows excellent conformity with prior studies. Simulation results suggestthat the TC deteriorates significantly with increasing concentration of carbon doping. It is revealed that incorporating only 5% of carbon dopants can reduce the TC of silicene by ~ 71%. Meanwhile, with the increase in temperature from 100 K to 600 K, the thermal conductivities of both pristine and carbon-doped silicene are also found to decline dramatically by ~14 W/m.K and ~9 W/m.K, respectively. The vacancy defect study reveals that thermal conductivities of both pure and carbon-doped silicene are also a strong function of vacancy concentration and can be reduced by ~ 58% by removing only 1% of silicon atom from the pristine nanosheet. It is further disclosed that the impact of vacancy on regulating the TC is more pronounced in pristine silicene than the carbon-doped silicene. To obtain a detailed insight into the thermal transport mechanism, phonon density of states (PDOS) is computed using the fast Fourier transform of the atomic velocity autocorrelation function. The PDOS discloses interesting phonon spectrum features under impurity doping, temperature variation, and increased vacancy concentration. Overall, this study offers a comprehensive roadmap for engineering the thermal conductivity of silicene and will grease the wheels for designing efficient thermal management systems for the present silicon-based semiconductor industry.