An immoral act considered to be a transgression against divine law.
He confessed his sin to the priest during the church service.
A serious or regrettable fault, offense, or omission.
It was considered a sin to waste food in their household.
(mathematics) Abbreviation of sine, the trigonometric function giving the ratio of the length of the side opposite a given acute angle to the hypotenuse in a right-angled triangle.