Copious, abundant (5)
I believe the answer is:
ample
I believe this clue is a double definition.
'copious' is the first definition.
(synonyms)
'abundant' is the second definition.
(associated in meaning)
(Other definitions for ample that I've seen before include "Sealed glass container for dose of medicine" , "Big" , "Fairly large" , "Plenty, more than enough" , "Plenteous" .)