na-adjective
Describes something visually striking, often in a bold or extravagant way. Similar to 派手 (はで) but with a softer, more elegant nuance.
彼女のドレスは派手やかで、パーティーで目立っていた。
Her dress was showy and stood out at the party.
この絵は色使いが派手やかだ。
This painting has flamboyant colors.
Derived from 派手 (はで, 'showy') with the adjectival suffix やか, which adds a softer, more descriptive quality. The exact historical derivation is uncertain, but it follows a pattern seen in other やか-ending adjectives.