clabber (n.)

also bonny-clabber, "clotted or coagulated soured milk," 1620s (in shortened form clabber), from Modern Irish bainne "milk" (from Middle Irish banne "drop," also, rarely, "milk"; cognate with Sanskrit bindu- "drop") + claba "thick." Compare Irish and Gaelic clabar "mud," which sometimes has made its way into English (Yeats, etc.).