lowliness vs lower rank

lowliness and lower rank both are nouns.

Word	Noun	Adjective	Verb	Adverb
lowliness	Yes	No	No	No
lower rank	Yes	No	No	No

As nouns, lower rank is a hyponym of lowliness; that is, lower rank is a word with a more specific, narrower meaning than lowliness:

lowliness: a position of inferior status; low in station or rank or fortune or estimation
lower rank: the state of being inferior

Other hyponyms of lowliness include inferiority, lower status, smallness.

lowliness (noun)	lower rank (noun)
a position of inferior status; low in station or rank or fortune or estimation	the state of being inferior
the state of being humble and unimportant