c.1746, "wanting sense," a British dialectal word, from gome "notice, understanding" (c.1200), from Old Norse gaumr "care, heed," of unknown origin; + -less.
Stupid; slow-witted; dumb
[1746+ British; fr British dialect gaumless, ''half-silly,'' lacking gaum, ''understanding''; the dated sense is in the form gaumless; the entry spelling is found by 1883]