didapper

noun

1. A small diving water bird frequenting rivers and fresh waters, specifically a little grebe or dabchick.

   “The misery of man may fitly be compar'd to a Di­dapper, who when she is under water, past our sight, and indeed can seem no more to us, rises again; […]”

2. (derogatory, obsolete)A scoundrel, a worthless person

   “If a Martin can play at cheſtes, as well as his nephewe the ape, he ſhall knowe what it is for a ſcaddle pawne, to croſſe a Biſhop in his owne walke. Such dydoppers must be taken vp, els theile not ſtick to check the king.”

   “In this towne two Cut-purſes were taken, that with other two of their companions followed mee from Lõdon (as many better diſpoſed perſons did): but theſe two dy-doppers gaue out when they were apprehended, that they had laid wagers and betted about my iourney; […]”