Meaning

adjective unpleasantly and excessively suave or ingratiating in manner or speech

originFrom Middle English fulsom, equivalent to full + -some. The meaning has evolved from an original positive connotation "abundant" to a neutral "plump" to a negative "overfed". In modern usage, it can take on any of these inflections. See usage note. The negative sense "offensive, gross; disgusting, sickening" developed secondarily after the 13th century and was influenced by Middle English foul…

Etymology from Wiktionary, CC BY-SA 3.0