jealous vs overjealous

jealous and overjealous both are adjectives.

Word	Noun	Adjective	Verb	Adverb
jealous	No	Yes	No	No
overjealous	No	Yes	No	No

As adjectives, jealous and overjealous are synonyms defined as:

jealous and overjealous: suspicious or unduly suspicious or fearful of being displaced by a rival

Other synonyms of jealous include green-eyed.

jealous (adjective)	overjealous (adjective)
showing extreme cupidity; painfully desirous of another's advantages	suspicious or unduly suspicious or fearful of being displaced by a rival
suspicious or unduly suspicious or fearful of being displaced by a rival