packsack vs back pack

packsack and back pack both are nouns.

Word	Noun	Adjective	Verb	Adverb
packsack	Yes	No	No	No
back pack	Yes	No	No	No

As nouns, packsack and back pack are synonyms defined as:

packsack and back pack: a bag carried by a strap on your back or shoulder

Other synonyms of packsack include backpack, haversack, knapsack, rucksack.

packsack (noun)	back pack (noun)
a bag carried by a strap on your back or shoulder	a bag carried by a strap on your back or shoulder