Latin paluster 'swampy, marshy' < palus (paludis) 'swamp, fen, marsh'. Cf. OHG fel(a)wa, NHG Felber 'willow tree', lit. 'swamp-tree'; from PIE root *pel- 'to pour, flow, fill' whence English full, Latin plenus, Skt purna (as in Annapurna 'full of food (edibles)', also Latin plebs 'people, the masses'.