formal sin

In theology, formal sin refers to an act that is both morally wrong in itself and recognized as such by the person committing it, thus incurring personal guilt. This is distinct from material sin, where an act is wrong but the perpetrator is unaware of its wrongfulness.1

Formal sin is a type of actual sin, which is any sin traceable to the personal will of the sinner, as opposed to original sin (the inherited condition of sinfulness). Actual sins can be further categorized by their gravity:12

• Mortal sin: A grave sin committed with full knowledge and consent, representing a deliberate turning away from God that severs sanctifying grace.1
• Venial sin: A less serious sin, often committed without full awareness, which weakens but does not completely block the connection with God.13

Both Judaism and Christianity view sin as a deliberate violation of God's will, often stemming from pride or disobedience.1