monotone vs droning

monotone and droning both are nouns.

Word	Noun	Adjective	Verb	Adverb
monotone	Yes	Yes	No	No
droning	Yes	No	No	No

As nouns, monotone and droning are synonyms defined as:

Other synonyms of monotone include drone.

monotone (noun)	droning (noun)
an unchanging intonation	an unchanging intonation
a single tone repeated with different words or different rhythms (especially in rendering liturgical texts)

monotone (adjective)	droning (adjective)
of a sequence or function; consistently increasing and never decreasing or consistently decreasing and never increasing in value
sounded or spoken in a tone unvarying in pitch