We introduce a new particle distribution function in plasma physics called the subtracted-kappa (S-K) distribution. This new distribution incorporates a loss-cone feature and an enhanced high-energy tail characterized by the spectral index κ. The S-K distribution is a generalization of the well-known subtracted-Maxwellian and approaches the latter distribution in the limit as κ→∞. Further, the S-K distribution usefully includes the bi-kappa and kappa-loss-cone distributions as special cases. Two sources of free plasma energy are provided by the S-K distribution, namely, the loss cone property and the thermal anisotropy. Both free energy sources can excite wave growth. In this paper, we briefly consider the influence of the S-K distribution on three wave phenomena: (a) linear growth of whistler-mode waves generated by an injection of hot electrons into a cold plasma, (b) dispersion of R-mode and L-mode electromagnetic waves in a hot plasma, and (c) transition from linear to nonlinear growth of electromagnetic waves as determined by a critical boundary in the input-parameter space. There are many possibilities for future projects involving the S-K distribution. Charged particle distributions in space typically possess a pronounced high-energy tail that can be modeled approximately by a kappa distribution, and so the S-K distribution is an ideal tool for analyzing kinetic waves and microinstabilities in space plasmas.