Fate tried to conceal him by naming him Smith.

Holmes’s line plays on the idea that a common name can act as camouflage. “Smith,” one of the most ordinary surnames in English, becomes a kind of disguise that “Fate” applies to someone otherwise destined to stand out. The wit depends on the contrast between anonymity (a name that blends into the crowd) and distinction (a person whose abilities or achievements resist being hidden). More broadly, the remark suggests that identity and reputation are not determined by labels: even the most generic social markers cannot ultimately obscure exceptional character or accomplishment.