unglamorous vs humdrum

unglamorous is not a noun while humdrum is a noun.

Word	Noun	Adjective	Verb	Adverb
unglamorous	No	Yes	No	No
humdrum	Yes	Yes	No	No

As adjectives, unglamorous and humdrum are synonyms defined as:

Other synonyms of unglamorous include commonplace, prosaic, unglamourous.

unglamorous (noun)	humdrum (noun)
	the quality of wearisome constancy, routine, and lack of variety

unglamorous (adjective)	humdrum (adjective)
not challenging; dull and lacking excitement	tediously repetitious or lacking in variety
	not challenging; dull and lacking excitement