This book deals with the oft-neglected tensions between perspicuity and fuzziness in specialised communication. It describes the manifestations, functions and implications of indeterminacy phenomena in a range of LSP specialisations where it has been customary to expect precision and consistency. The volume presents case studies and methodological frameworks that draw on theoretical, anthropological and cognitive linguistics, safety-critical translating, history and theory of terminology studies, development of ontologies, software localisation, jurisprudence, macroeconomics and interoperability of digital knowledge representation resources.