A patient speaks in grammatically correct, fluent sentences but repeatedly cannot find the name of common objects shown to him, instead describing what each one is used for; his comprehension and grammar are otherwise entirely intact. What is this?

This is nominal aphasia: prominent, disproportionate difficulty naming objects despite an otherwise intact vocabulary and grammar, with the person talking fluently around the object using description rather than its actual name, exactly as described. It is not central aphasia, since nominal aphasia differs from central aphasia in that grammar and sentence structure remain largely intact; the deficit is specific to naming, whereas central aphasia disturbs grammar and syntax together with comprehension and production. It is not expressive aphasia more broadly, which involves difficulty producing spoken language generally, not a single, isolated naming deficit within fluent surrounding speech. And it is not pure word-dumbness, which is a total inability to speak at all, not a selective naming difficulty within otherwise fluent speech.