Euaggelizō (G2097) means to bring or announce good news, to proclaim the gospel. It combines eu ('good, well') and angelos ('messenger') — to be a good-news-messenger. It appears approximately 54 times in the New Testament and is the verbal form of euaggelion (G2098, 'gospel'). The LXX uses it to translate basar (H1319, 'to bring good tidings'), linking it to Isaiah's great proclamations of coming salvation (Isaiah 40:9; 52:7; 61:1).
Euaggelizō is the activity at the center of the New Testament mission. Jesus began his ministry by euangelizomenos — preaching the good news of the kingdom (Luke 4:18, 43; 8:1). After the resurrection, the apostles understood their primary calling as the proclamation of this good news to all peoples: 'Woe to me if I do not preach the gospel!' (1 Corinthians 9:16).
The content of the euaggelion is specific: the death, burial, and resurrection of Jesus Christ for sins, according to the Scriptures (1 Corinthians 15:1-4). Paul declares that even if an angel were to preach a different gospel, it would be anathema (Galatians 1:8). The gospel is not a message about how to live better — it is an announcement of something that has already happened: God has acted in Christ to rescue sinners. Euaggelizō is the heralding of this royal decree.