sou'-sou'-east vs south-southeast

sou'-sou'-east is a noun but south-southeast is not a noun.

Word	Noun	Adjective	Verb	Adverb
sou'-sou'-east	Yes	No	No	Yes
south-southeast	No	No	No	Yes

As adverbs, sou'-sou'-east and south-southeast are synonyms defined as:

sou'-sou'-east and south-southeast: to, toward, or in the south southeast

sou'-sou'-east (noun)	south-southeast (noun)
the compass point midway between south and southeast

sou'-sou'-east (adverb)	south-southeast (adverb)
to, toward, or in the south southeast	to, toward, or in the south southeast