At last, only thirteen Men remained, and Ragnor was one of these: a faithful servant and soldier of the House of Bëor. One fateful night, as the outlaws slept by the shores of a mountain lake, they were set upon by Orcs and slain to a Man. Beren was absent from the camp, and survived, but Ragnor and all his companions were lost.
The Etymologies gives us an adjective, ragna, that means 'crooked', but there's no direct evidence to link this with Ragnor's name. (The History of Middle-earth Volume 5, The Lost Road and Other Writings III The Etymologies).