[Perhaps from an unattested American colonial Dutch use of Dutch poppekak, doll's excrement (in contemporary Dutch, found mostly in variants of the expression zo fijn als gemalen poppekak, excessively pious (literally, as fine as powdered doll's excrement)) : pop, doll (from Middle Dutch poppe, from Vulgar Latin *puppa, from Latin pūpa) + kak, excrement (from kakken, to defecate, from Middle Dutch kacken, from Latin cacāre; see kakka- in the Appendix of Indo-European roots).]