The Greek ekkoptō means to cut off or cut down — as an ax to a tree, or pruning shears to a branch. John the Baptist uses it in his most urgent warning: 'The ax is already at the root of the trees, and every tree that does not produce good fruit will be cut down (ekkoptō) and thrown into the fire' (Matthew 3:10; Luke 3:9). Jesus repeats the same warning in Matthew 7:19.
The image of ekkoptō — the ax at the root — is one of the most urgent metaphors in the Gospels. John the Baptist's preaching confronted religious complacency: mere genealogical connection to Abraham was insufficient. The demand was fruit. The judgment was imminent. Paul uses similar language in Romans 11:22 (branches that are cut off) and 2 Corinthians 11:12 (cutting off occasion from his opponents). The consistent teaching: fruitlessness leads to removal. But the same power that can cut down can also graft in (Romans 11:23).