The verb deigmatizō means to expose publicly, to make a spectacle of someone, or to put to open shame. It carries the connotation of a public parade of disgrace — holding someone up before all as an example of defeat or failure. In Matthew 1:19, Joseph did not want to deigmatizō Mary when he found she was pregnant.
The two New Testament uses of deigmatizō present a remarkable contrast. In Matthew 1:19, righteous Joseph chooses mercy over public disgrace — a picture of the gospel's spirit. In Colossians 2:15, Paul uses a related term to describe what Christ did to the powers: 'he made a public spectacle of them, triumphing over them by the cross.' The cross — itself an instrument of public shame — became the very means by which Christ publicly disgraced sin, death, and the powers of darkness. What was meant as Jesus' shame became their defeat.