Luxuriant means growing thickly and richly. Luxuriant growth, a luxuriant beard, luxuriant vegetation.
It is about abundance rather than expense, which is what separates it from luxurious, and the two are confused constantly. It belongs to hair and to vegetation above all.
1adjectiveluxuriantGrowing thickly and richly.
“She had long, luxuriant hair that fell to her waist.”
luxuriant is a quality.
Also accepted in games: lush
Latin luxurians comes from luxuria, rankness or excess.
Latin
lūxuriāns
English, today
luxuriant
Built from
Latin lūxuriāns, present participle of lūxuriō, itself from lūxuria (“luxury, excess”). Equivalent to luxury + ant.
Etymology from Wiktionary, CC BY-SA