by 1650s, "of or pertaining to Abdera," in Thrace, whose citizens were proverbial as provincials who would laugh at anything or anyone they didn't understand (Abderian laughter), making their town the Hellenic equivalent of Gotham (q.v.). Especially (or alternatively) as it was the birthplace of Democritus the atomist, the "Laughing Philosopher" (born c. 460 B.C.E.) who observed human follies.
"light stick used by painters to support the painting hand," 1650s, from Dutch maalstok, literally "painting stick," from mallen "to paint," from Proto-Germanic *mal- (source also of Old Norse mæla, Old High German malon "trace, draw, paint," German malen "to paint"), from mal "spot, mark, stain," perhaps from the same root as Greek melas "black" (see melano-), but the original sense is not color but marking. With stock "stick" (see stock (n.1)).