taru-adjective, adverb taking the 'to' particle
gorgeous; brilliant; dazzling; ornate
Describes something visually splendid, richly decorated, or brilliantly colorful. Often used in literary or formal contexts. The compound 絢爛豪華 is very common.
絢爛たる宮殿の装飾に目を奪われた。
I was captivated by the gorgeous decorations of the palace.
彼女は絢爛とした衣
She appeared at the party in a dazzling costume.
豪華 means 'luxurious' or 'extravagant' and is more common in everyday speech. 絢爛 emphasizes visual brilliance and ornate beauty, often in a literary or formal register.
華やか means 'showy' or 'glamorous' and is a standard adjective. 絢爛 is more intense and literary, suggesting dazzling, almost overwhelming splendor.
The kanji 絢 means 'brilliant design' or 'gorgeous pattern', and 爛 means 'brilliant' or 'glowing'. Together they form a compound describing dazzling brilliance and ornate beauty. The exact historical derivation is uncertain, but the word has been used in literary Japanese for centuries.