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We report the first near-infrared study of the $Ar-H2O$ van der Waals complex. Three bands, all involving the asymmetric stretch of the $H_{2}O $ submit, are observed. In conjunction with far-infrared data of Cohen $etal.1$, these allow determination of the intermolecular angular potential for the ground vibrational state of the complex. We find a smaller barrier for in-plane versus out-of-plane internal rotation of the water molecule within the complex. One of the bands exhibits perturbations of frequencies and line widths which reveal a resonance with a predissociative, $H2O$ symmetric scratch excited state. Analysis of the data provides evidence for both intra and intermolecular vibrational energy flow in the complex.