The English verbal prefix out- gives rise to at least two semantic categories: comparative forms as in to outplay someone and locative forms as in to outstream from somewhere. While most available studies on the comparative sense rely on insufficient databases, systematic studies on the actual behavior of locative verbal out-forms are lacking altogether. Building on a set of more than 1,500 tokens culled from corpora, this study is the first to systematically analyze, formalize, and contrast the two senses. The formal analysis will be couched in frame semantics and model both individual attested examples as well as lexeme-formation rules based on generalizations. Formalizations of the two prefixes, and their implications, are shown to speak against an analysis of one underlying, underspecified prefix. Locative out- essentially functions as a morphologically bound, and highly restricted, version of out- as a particle, while comparative out- is a highly specialized, idiosynchratic construction.