tenderness vs affection

tenderness and affection both are nouns.

Word	Noun	Adjective	Verb	Adverb
tenderness	Yes	No	No	No
affection	Yes	No	No	No

As nouns, tenderness and affection are synonyms defined as:

Other synonyms of tenderness include affectionateness, fondness, heart, philia, warmheartedness, warmness.

tenderness (noun)	affection (noun)
a tendency to express warm and affectionate feeling	a positive feeling of liking
a feeling of concern for the welfare of someone (especially someone defenseless)
a positive feeling of liking
warm compassionate feelings
a pain that is felt (as when the area is touched)