relational adjective re·la·tio·naladjective uncommon noun 1. an adjective that classifies its noun (e.g., `a nervous disease'' or `a musical instrument'') Synonymsrelational adjectiveclassifying adjective Related words Broader terms adjective Narrower terms pertainym WordNet 2.1 (Princeton University). WordNet 2.1 Copyright Princeton University. All rights reserved.