dizziness vs symptom

dizziness and symptom both are nouns.

Word	Noun	Adjective	Verb	Adverb
dizziness	Yes	No	No	No
symptom	Yes	No	No	No

As nouns, symptom is a hypernym of dizziness; that is, symptom is a word with a broader meaning than dizziness:

dizziness: a reeling sensation; a feeling that you are about to fall
symptom: (medicine) any sensation or change in bodily function that is experienced by a patient and is associated with a particular disease

dizziness (noun)	symptom (noun)
a reeling sensation; a feeling that you are about to fall	anything that accompanies X and is regarded as an indication of X's existence
	(medicine) any sensation or change in bodily function that is experienced by a patient and is associated with a particular disease