grinning vs simper

grinning and simper both are nouns.

Word	Noun	Adjective	Verb	Adverb
grinning	Yes	No	No	No
simper	Yes	No	Yes	No

As nouns, simper is a hyponym of grinning; that is, simper is a word with a more specific, narrower meaning than grinning:

grinning: a facial expression characterized by turning up the corners of the mouth; usually shows pleasure or amusement
simper: a silly self-conscious smile

Other hyponyms of grinning include smirk.

grinning (noun)	simper (noun)
a facial expression characterized by turning up the corners of the mouth; usually shows pleasure or amusement	a silly self-conscious smile

grinning (verb)	simper (verb)
	smile affectedly or derisively