The words κόπος, πόνος, and ὠδίν have similar meanings, but there are different ideas connected with them. ὠδίν occurs but four times in the N. T. It refers literally to the pangs of a woman in childbirth, in which sense it occurs in 1 Thess. 5:3; twice it refers to the pangs that will seize the wicked when God's judgments are poured out upon the earth, Matt. 24:8; Mark 13:8; and once in reference to the pains of death endured by the Lord. Acts 2:24.
μόχθος (from μογέω, 'to labor, be in distress') occurs three times in the N. T. It has been judged to refer to the toil which is the lot of man in this world of sin, answering to "in the sweat of thy face shalt thou eat bread." This seems to be confirmed by Paul's twice using it in reference to his labors (travail, A. V.), having to work night and day in addition to his apostolic work. 1 Thess. 2:9; 2 Thess. 3:8. In 2 Cor. 11:27 it is joined with κόπος where Paul describes his life of labor and toil ("weariness [κό.] and painfulness [μό.]" A. V.), as well as the dangers he passed through.
πόνος (from πένομαι, 'to labor ') occurs three times in the N. T., twice referring to the ‘distress' that will attend the pouring out of God's judgments, and once to when there will be no distress or pain. Rev. 16:10, 11; 21:4. (Some editors read πόνος in Col. 4:13 instead of ζῆλος.) The word is used by the LXX for the rigorous bondage of the Israelites in Egypt. Exod. 2:11. It seems to express the extremity of distress.
κόπος (from κόπτω, 'to strike ') occurs often in the N. T. In the A. V. it is translated ‘weariness' in 2 Cor. 11:27; ‘trouble' and ‘labor' often. Perhaps the weariness of labor and trouble marks this word.
In the LXX three of the above words are attributed to Job's wife in her despair under the dealings of Satan. "The pangs (ὠδῖνες) and pains (πόνοι) of my womb which I bore in vain with sorrows (μόχθων)"—having lost her sons and daughters. Job 2:9.