I'm not really attempting to set a new record for annoying posts of unusual words, it's just turning out that way because I can't get the last few common bloody words! This one is rare but not obsolete when used as an adjective, and is also recorded by Webster as a Scottish adverb, for good measure.
lourd /0lʊəd/ adjective & noun. Now rare. LME.
[ORIGIN Old French & Modern French = heavy, (formerly) foolish.]
► A adjective. Orig., sluggish, dull, coarse, stupid. Later, heavy; gloomy. LME.
► †B noun. A coarse fellow, a lout. Only in L16.