lubber (n.) Look up lubber at
mid-14c., "big, clumsy, stupid fellow who lives in idleness," from lobre, earlier lobi "lazy lout," probably of Scandinavian origin (compare Swedish dialectal lubber "a plump, lazy fellow"). But OED suggests a possible connection with Old French lobeor "swindler, parasite," with sense altered by association with lob (n.) in the "bumpkin" sense. Sometimes also Lubbard (1580s), with pejorative suffix -ard.

Since 16c. mainly a sailors' word for those inept or inexperienced at sea (as in landlubber), but earliest attested use is of lazy monks (abbey-lubber). Compare also provincial English lubberwort, name of the mythical herb that produces laziness (1540s), Lubberland "imaginary land of plenty without work" (1590s).
lubber (v.) Look up lubber at
"to sail clumsily; to loaf about," 1520s, from lubber (n.). Related: Lubbered; lubbering.