Webster's Revised Unabridged Dictionary · 1913

Jealous

Jealous , adjective

[Old English jalous, gelus, Old French jalous, French jaloux, Late Latin zelosus zealous, from zelus emulation, zeal, jealousy, Greek zh^los. See Zeal, and compare Zealous.]

1.
Zealous; solicitous; vigilant; anxiously watchful.
I have been very jealous for the Lord God of hosts. — Kings xix. 10
How nicely jealous is every one of us of his own repute! — Dr. H. More
2.
Apprehensive; anxious; suspiciously watchful.
'This doing wrong creates such doubts as these, Renders us jealous and disturbs our peace. — Waller
The people are so jealous of the clergy's ambition. — Swift
3.
Demanding exclusive devotion; intolerant of rivalry.
Thou shalt worship no other God; for the Lord, whose name is Jealous, is a jealous God. — Ex. xxxiv. 14
4.
Disposed to suspect rivalry in matters of interest and affection; apprehensive regarding the motives of possible rivals, or the fidelity of friends; distrustful; having morbid fear of rivalry in love or preference given to another; painfully suspicious of the faithfulness of husband, wife, or lover.
If the spirit of jealousy come upon him, and he be jealous of his wife. — Num. v. 14
To both these sisters have I sworn my love: Each jealous of the other, as the stung Are of the adder. — Shakespeare
It is one of the best bonds, both of chastity and obedience, in the wife, if she think her husband wise; which she will never do if she find him jealous. — Bacon