An evangelist — one who proclaims the euangelion (good news/gospel). In the New Testament, this is both a function (preaching the gospel) and a recognized role in the early church. Philip is specifically called 'the evangelist' (Acts 21:8), and Paul tells Timothy to 'do the work of an evangelist' (2 Timothy 4:5).
The euangelistes is one of Christ's gifts to the church (Ephesians 4:11), distinct from apostles, prophets, pastors, and teachers. The role emphasizes proclamation to the unconverted — carrying the good news beyond the church walls. Philip's example is instructive: he went to Samaria, preached to the Ethiopian eunuch, and moved wherever the Spirit directed. The evangelist is the church's offensive weapon — always advancing, always proclaiming.