An abstract noun is a noun that describes something you cannot touch (not a thing, not a person), for example: love, anger, education, relationship... It's a noun, meaning it can take an article and an adjective.
An adjective qualifies a noun, for example: good, bad, blue, healthy, warm, cold... You can speak of a "warm relationship, a good education, ...", and also of "a warm blanket, a good person, ..."