rucksack vs packsack

rucksack and packsack both are nouns.

Word	Noun	Adjective	Verb	Adverb
rucksack	Yes	No	No	No
packsack	Yes	No	No	No

As nouns, rucksack and packsack are synonyms defined as:

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

Other synonyms of rucksack include back pack, backpack, haversack, knapsack.

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