Sc. and north. dial. Also sproug, sprog. [Of obscure origin: the form spug (with variant spyug) is also common in Sc. and Eng. dial.] A sparrow.

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1815.  Scott, Guy M., xi. John Wilson was a blustering kind of chield, without the heart of a sprug.

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1886–.  in Eng. Dial. Dict.

3