As nouns the difference between jest and jess
is that
jest is (archaic) an act performed for amusement; a joke while
jess is (falconry) a short strap fastened around the leg of a bird used in falconry, to which a leash may be fastened or
jess can be a compact coal-like, velvet-black mineral, with a polish making it fit for use in jewelry.
As verbs the difference between jest and jess
is that
jest is to tell a joke; to talk in a playful manner; to make fun of something or someone while
jess is (falconry) to fasten a strap around the leg of a hawk.