time to come vs manana

time to come and manana both are nouns.

Word	Noun	Adjective	Verb	Adverb
time to come	Yes	No	No	No
manana	Yes	No	No	No

As nouns, manana is a hyponym of time to come; that is, manana is a word with a more specific, narrower meaning than time to come:

Other hyponyms of time to come include kingdom come, by-and-by, offing, tomorrow.

time to come (noun)	manana (noun)
the time yet to come	an unspecified time in the future