As nouns the difference between pounce and pouncer
is that
pounce is (historical) a type of fine powder, as of sandarac, or cuttlefish bone, sprinkled over wet ink to dry the ink after writing or
pounce can be the claw or talon of a bird of prey while
pouncer is one who pounces.
As a verb pounce
is to sprinkle or rub with pounce powder or
pounce can be to leap into the air intending to seize someone or something.