astrology vs horoscopy

astrology and horoscopy both are nouns.

Word	Noun	Adjective	Verb	Adverb
astrology	Yes	No	No	No
horoscopy	Yes	No	No	No

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

astrology: a pseudoscience claiming divination by the positions of the planets and sun and moon
horoscopy: the drawing up and interpretation of horoscopes

astrology (noun)	horoscopy (noun)
a pseudoscience claiming divination by the positions of the planets and sun and moon	the drawing up and interpretation of horoscopes