'Ôyêb (אוֹיֵב, Strong's #341), “enemy.” 'Ôyêb has an Ugaritic cognate. It appears about 282 times in biblical Hebrew and in all periods. In form, the word is an active infinitive (or more precisely, a verbal noun).
This word means “enemy,” and is used in at least one reference to both individuals and nations: “… In blessing I will bless thee, and in multiplying I will multiply thy seed as the stars of the heaven, and as the sand which is upon the sea shore; and thy seed shall possess the gate of his enemies” (Gen. 22:17—the first occurrence). “Personal foes” may be represented by this word: “If thou meet thine enemy’s ox or his ass going astray, thou shalt surely bring it back to him again” (Exod. 23:4). This idea includes “those who show hostility toward me”: “But mine enemies are lively, and they are strong; and they that hate me wrongfully are multiplied” (Ps. 38:19).
One might be an “enemy” of God: “… The Lord will take vengeance on his adversaries, and he reserveth wrath for his enemies” (Nah. 1:2). God is the “enemy” of all who refuse to submit to His lordship: “But they rebelled, and vexed his holy Spirit: therefore he was turned to be their enemy …” (Isa. 63:10).
Tsâr (צָר, Strong's #6862), “adversary; enemy; foe.” This noun occurs 70 times in the Hebrew Old Testament, mainly in the Psalms (26 times) and Lamentations (9 times). The first use of the noun is in Gen. 14:20: “And blessed be the most high God, which hath delivered thine enemies into thy hand.”
Tsâr is a general designation for “enemy.” The “enemy” may be a nation (2 Sam. 24:13) or, more rarely, the “opponent” of an individual (cf. Gen. 14:20; Ps. 3:1). The Lord may also be the “enemy” of His sinful people as His judgment comes upon them (cf. Deut. 32:41-43). Hence, the Book of Lamentations describes God as an “adversary” of His people: “He hath bent his bow like an enemy [‘oyeb]: he stood with his right hand as an adversary [tsâr], and slew all that were pleasant to the eye in the tabernacle of the daughter of Zion: he poured out his fury like fire” (Lam. 2:4).
The word tsâr has several synonyms: ’oyeb, “enemy” (cf. Lam. 2:5); sone’, “hater” (Ps. 44:7); rodep, “persecutor” (Ps. 119:157); ‘arits, “tyrant; oppressor” (Job 6:23).
In the Septuagint, tsâr is generally translated by echthros (“enemy”). The KJV gives these translations: “enemy; adversary; foe.”