altogether vs entirely

altogether is a noun but entirely is not a noun.

Word	Noun	Adjective	Verb	Adverb
altogether	Yes	No	No	Yes
entirely	No	No	No	Yes

As adverbs, altogether and entirely are synonyms defined as:

altogether and entirely: to a complete degree or to the full or entire extent; Completely or entirely

Other synonyms of altogether include all, completely, right, totally, whole, wholly.

altogether (noun)	entirely (noun)
informal terms for nakedness

altogether (adverb)	entirely (adverb)
with everything included or counted	to a complete degree or to the full or entire extent; Completely or entirely
with everything considered (and neglecting details)	without any others being included or involved
to a complete degree or to the full or entire extent; Completely or entirely