afterglow vs pleasantness

afterglow and pleasantness both are nouns.

Word	Noun	Adjective	Verb	Adverb
afterglow	Yes	No	No	No
pleasantness	Yes	No	No	No

As nouns, pleasantness is a hypernym of afterglow; that is, pleasantness is a word with a broader meaning than afterglow:

afterglow: the pleasure of remembering some pleasant event
pleasantness: the feeling caused by agreeable stimuli; one pole of a continuum of states of feeling

afterglow (noun)	pleasantness (noun)
the pleasure of remembering some pleasant event	the quality of giving pleasure
a glow sometimes seen in the sky after sunset	the feeling caused by agreeable stimuli; one pole of a continuum of states of feeling