If you have a copious amount of something, you have a lot of it. If you take copious notes, you'll do well when it comes time for review sessions — unless you can't read your own handwriting.
Copious comes from the Latin copia, meaning "abundance." You can use copious for something quantitative, like your copious admirers, or for something qualitative, like the copious gratitude you feel for your admirers. You will often see the word amounts following copious since the adjective is often used to modify a measurement of something — like copious amounts of wine or copious amounts of hair gel.