According to Catholicism, a venial sin is a lesser sin that does not result in a complete separation from God and eternal damnation in Hell as an unrepented mortal sin would.[1][2][3] A venial sin consists in acting as one should not, without the actual incompatibility with the state of grace that a mortal sin implies; they do not break one's friendship with God, but injure it.[4]
Pieper1950
was invoked but never defined (see the help page).