We lack insight into the dynamics of antibiotic inhibitory and resistance phenotypes and their roles in mediating interactions among microbial species in natural environments. Antibiotics can act as weapons, mediating antagonistic interactions, or signals, mediating a broader range of antagonistic, neutral, manipulative, or synergistic interactions. Both the role of antibiotics and the interactions they mediate are critical to the coevolutionary dynamics of interacting populations. Fitness tradeoffs constrain the capacity for individual bacterial populations to be efficient at resource use, highly inhibitory to other microbes, and broadly resistant to antibiotics at the same time. Unraveling the phenotypic characteristics of interacting microbial populations provides guidance for discovering antibiotics, managing microbial communities, and identifying factors that maintain antibiotic resistance in these populations.