pack rat vs packrat

pack rat and packrat both are nouns.

Word	Noun	Adjective	Verb	Adverb
pack rat	Yes	No	No	No
packrat	Yes	No	No	No

As nouns, pack rat and packrat are synonyms defined as:

pack rat and packrat: any of several bushy-tailed rodents of the genus Neotoma of western North America; hoards food and other objects

Other synonyms of pack rat include bushytail woodrat, Neotoma cinerea, trade rat.

pack rat (noun)	packrat (noun)
any of several bushy-tailed rodents of the genus Neotoma of western North America; hoards food and other objects	any of several bushy-tailed rodents of the genus Neotoma of western North America; hoards food and other objects
someone who collects things that have been discarded by others	a collector of miscellaneous useless objects