observer vs discoverer

observer and discoverer both are nouns.

Word	Noun	Adjective	Verb	Adverb
observer	Yes	No	No	No
discoverer	Yes	No	No	No

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

observer: a person who becomes aware (of things or events) through the senses
discoverer: someone who is the first to observe something

observer (noun)	discoverer (noun)
a person who becomes aware (of things or events) through the senses	someone who is the first to observe something
an expert who observes and comments on something	someone who is the first to think of or make something