adj. 1 resentful of rivalry in love. 2 (often foil. by oJ) envious (of a person etc.). 3 (often foil. by ot) fiercely protective (of rights etc.). 4 (of God) intolerant of disloyalty. 5 (of inquiry, supervision, etc.) vigilant. jealously ado. [medieval Latin zelosus: related to ZEAL]