apprehensive and suspicious of rivalry, esp in sexual love
(+ of) resentful and envious of an advantage, possession, etc that somebody else has or is believed to have
vigilant in guarding a possession, right, etc
He was jealous of his honour
intolerant of rivalry or unfaithfulness
The Lord your God is a jealous God — Bible
jealously adv
jealousness noun
jealousy noun
[Middle English jelous via Old French from late Latin zelus zeal, from Greek zēlos]