Someone whose mind is always preoccupied with any beautiful or sexy properties about the sine curve or function.

Arthur is such a sin-ful fellow, who is always trying to excite any geeky girls with these trig relationships:

a) sin x = x – x³/3! + x⁵/5! – x⁷/7! + ⋯

b) sin 2A + sin 2B + sin 2C = 4 sin A sin B sin C, where A, B, and C are the angles in a triangle.

b) ⌽ = –2 sin 666°—when the number of the beast, phi, and sine are in an eternal triangle.

a) sin x = x – x³/3! + x⁵/5! – x⁷/7! + ⋯

b) sin 2A + sin 2B + sin 2C = 4 sin A sin B sin C, where A, B, and C are the angles in a triangle.

b) ⌽ = –2 sin 666°—when the number of the beast, phi, and sine are in an eternal triangle.

via giphy

by MathPlus123 October 19, 2017

doing naughty things, being bad, doing something that society sees as bad or wrong, being evil, not caring, comiting a sin.

example 1:

person 1: Hey did u comit a sin last night?

person 2: Yes, i had a one night stand, if that's what you ment.

example 2:

I didn't listen to my parents. Oh, i'm so sinful.

example 3:

I like that hot ass guy with tattoos! He looks so sinful.

person 1: Hey did u comit a sin last night?

person 2: Yes, i had a one night stand, if that's what you ment.

example 2:

I didn't listen to my parents. Oh, i'm so sinful.

example 3:

I like that hot ass guy with tattoos! He looks so sinful.

by daymgirl January 06, 2010

by foxxylady May 14, 2006