This paper presents a case study in legacy lexical resource renewal through mutual expansion and cross-resource linking, involving two Italian lexical databases: ItalWordNet (IWN), a general-purpose WordNet, and MariTerm, a specialized maritime terminology resource. Both resources, developed in the early 2000s, face challenges due to outdated formats, incomplete cross-referencing, and structural inconsistencies despite overlapping coverage. Through a semi-automatic pipeline combining similarity scoring and manual validation, we expanded IWN with 1,160 maritime-specific semantic relations and created 363 new synsets, i.e, sets of synonymous terms sharing semantic properties and contextual interchangeability. At the same time, the pipeline created 751 mapping nodes from MariTerm to IWN and 759 in the opposite direction. The new MariTerm version, now featured in an official CLARIN repository, contains 27 new synsets with 38 new lemmas and comprehensive cross-resource integration. The process still revealed critical challenges in reusing legacy data: structural inconsistencies, missing metadata and duplicate entries. We demonstrate how strategic expansion and linking not only preserved valuable linguistic knowledge but enhanced both resources’ utility for specialized and general-purpose applications. The renewed databases exemplify how legacy resources can be revitalized through systematic reuse methodologies and straightforward rule-based algorithms, benefiting from reciprocal enrichment while achieving modern standards of interoperability and sustainability.