At the Christmas party she was dressed very extravagantly compared to others that were there.
Those who spend money extravagantly (adverb) and indulge in extravagance (noun) are called extravagant. (noun)
She dressed extravagantly, with a fur coat, diamond jewelry, and designer shoes, making heads turn wherever she went.
He walked by me extravagantly with his black people hair.
"Extravagantly" is an adverb.
Extravagantly is an adverb.
I am not writing a sentence using that word.
I can give you a sentence using the word galaxy.
a sentence using the word endotracheal
This is a sentence using the word aviator.
Excessively, extremely, extensively, overly...
I am saying a sentence using the word collagen.
This is a sentence using the word monomer. :P