Top definition
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.
via giphy
by MathPlus October 19, 2017
Get the mug
Get a Sin-ful mug for your father-in-law Abdul.
2
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.
by daymgirl January 06, 2010
Get the mug
Get a Sinful mug for your cat Jovana.
3
Horny; dealing with all thoughts of sex and its fantastic acts.
"I was so sinful last night that I almost had to change my panties," my friend Jackie would say.
by foxxylady May 14, 2006
Get the mug
Get a sinful mug for your sister Rihanna.
4
Term used by the spiritual and religious community for 'evil' actions deemed to have a somewhat deserved unforetelling or difficult circumstance. Usually linked to 'fleshly' behavior or desire.
His sinful action caused her to benefit in alimony.
by Zandroid August 18, 2017
Get the mug
Get a Sinful mug for your bunkmate Georges.