As nouns the difference between pendent and necklace
is that
pendent is while
necklace is an article of jewelry that is worn around the neck, most often made of a string of precious metal, pearls, gems, beads or shells, and sometimes having a pendant attached.
As an adjective pendent
is dangling, drooping, hanging down or suspended.
As a verb necklace is
(south africa) to informally execute by setting on fire a petrol-filled rubber tyre which has been put around the bound victim's neck.