hoarder
noun
hoard·er
| \ ˈhȯr-dər
\
\
plural hoarders
Definition of hoarder
: a person or animal that hoards
We love shopping, and logically so: we're planners and hoarders, and by stocking up on available goods now, we can weather lean times tomorrow.— Natalie Angier
specifically
: a person with hoarding disorder
She is someone who buys too much and doesn't throw anything away, even as the stuff piles up and impedes normal life—the textbook definition of a hoarder. — Steven Kurutz Most hoarders … know that their behavior is socially unacceptable and as a result actively conceal it from others. — Sandra G. Boodman