Strong's #6862: tsar (pronounced tsar)
 or tsar {tsawr}; from 6887; narrow; (as a noun) a tight place (usually figuratively, i.e. trouble); also a pebble (as in 6864); (transitive) an opponent (as crowding):--adversary, afflicted(-tion), anguish, close, distress, enemy, flint, foe, narrow, small, sorrow, strait, tribulation, trouble.
Brown-Driver-Briggs Hebrew Lexicon:
 / 
  tsar 
 
 1) narrow, tight
 2) straits, distress
 3) adversary, foe, enemy, oppressor
 4) hard pebble, flint
 
  Part of Speech: adjective
Relation: from H6887
  Same Word by TWOT Number:  1973a, 1973b, 1974a, 1975a
Usage:
This word is used 109 times:
Lamentations 2:17: "to rejoice over thee, he hath set up the horn  of thine adversaries."
Lamentations 4:12: "would not have believed that  the adversary and the enemy should have entered into the gates of Jerusalem."
Ezekiel 30:16: "and No shall be rent asunder, and Noph  shall have distresses daily."
Ezekiel 39:23: "I my face from them, and gave them into the hand  of their enemies: so fell they all by the sword."
Hosea 5:15: "till they acknowledge their offense, and seek my face:  in their affliction they will seek me early."
Amos 3:11: "saith the Lord GOD;  An adversary there shall be even round about the land; and he shall bring down thy strength"
Micah 5:9: "Thine hand shall be lifted up upon  thine adversaries, and all thine enemies shall be cut off."
Nahum 1:2: "and is furious; the LORD will take vengeance  on his adversaries, and he reserveth wrath for his enemies."
Zechariah 8:10: "to him that went out or came in because of  the affliction: for I set all men"