The Greek verb skandalizo (σκανδαλίζω) means to cause someone to stumble, sin, or fall away from faith. It derives from skandalon (a trap's trigger, a stumbling block). It appears about 29 times in the NT.
Skandalizo is one of the most serious words in Jesus' vocabulary. He warned with extreme language: 'If your hand causes you to stumble, cut it off' (Matthew 5:30; 18:8). Even more sobering: 'If anyone causes one of these little ones who believe in me to stumble, it would be better for them to have a large millstone hung around their neck' (Matthew 18:6). The cross itself is a skandalon (1 Corinthians 1:23) — it causes the unbelieving to stumble, but to the called it is the power of God. Ministry requires removing stumbling blocks and becoming none yourself.