Where does “sneaky” come from?

Sneaky derives from English sneak plus the Middle English suffix -y, which comes from Middle French -ie, ultimately tracing through Latin -ia and -ivus to Proto-Indo-European -kos.

sneaky (English): Difficult to catch due to constantly outwitting...

Definitions

Difficult to catch due to constantly outwitting...

Ancestry of “sneaky”, step by step

Step	Language	Word	Meaning
1	English	-y	Added to nouns and adjectives to form adjectives...
2	Middle English	-y	Designates an adjective, in many cases formed by...
3	Old English	-iġ	-y, -ic
4	Proto-West Germanic	-g	Forms adjectives from nouns and verbs with a...
5	Proto-Germanic	-gaz	-y
6	Proto-Indo-European	-ḱos	-y, -ic

Words derived from “sneaky”

sneakily
sneakiness

Every word from Proto-Indo-European -ḱos →Every word from English -y →Every word from Old English -iġ →