Meaning

noun a person who is regarded as underhanded and furtive and contemptible

noun someone who prowls or sneaks about; usually with unlawful intentions

noun someone acting as an informer or decoy for the police

originPossibly from Middle English sniken (“to creep, crawl”), from Old English snīcan (“to creep, crawl”), from Proto-West Germanic *snīkan, from Proto-Germanic *snīkaną (“to creep, crawl”), which is related to the root of snake. Compare Danish snige (“to sneak”), Swedish snika (“to sneak, hanker after”), Icelandic sníkja (“to sneak, hanker after”). Possibly related to snitch.

Etymology from Wiktionary, CC BY-SA 3.0