Obs. rare–1. [echoic: cf. RAP.] A noise made by knocking. In quot. attrib.

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1583.  Stanyhurst, Æneis, IV. (Arb.), 120.

        With nayles hir visadge skratching, and mightilye rapping
Her brest with thumping frap knocks, through rout she doth enter.

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