til now vs hitherto

til now and hitherto both are adverbs.

Word	Noun	Adjective	Verb	Adverb
til now	No	No	No	Yes
hitherto	No	No	No	Yes

As adverbs, til now and hitherto are synonyms defined as:

til now and hitherto: used in negative statement to describe a situation that has existed up to this point or up to the present time

Other synonyms of til now include as yet, heretofore, so far, thus far, until now, up to now, yet.

til now (adverb)	hitherto (adverb)
used in negative statement to describe a situation that has existed up to this point or up to the present time	used in negative statement to describe a situation that has existed up to this point or up to the present time