Main Difference
The main difference between Sweater and Hoodie is that the Sweater is a knitted garment for the upper body and Hoodie is a sweatshirt with a hood.
Sweater
A jumper(British English), or jersey, is a garment intended to cover the torso and arms. A jumper is either a pullover or a cardigan, distinguished in that cardigans open at the front while pullovers do not. In American English, a pullover may also be called a sweater. Some British dictionaries include cardigans as a type of jumper, while others do not; in the latter case, there is no hypernym equivalent to sweater covering both pullovers and cardigans.
Sweaters are worn by adults and children of all genders; often over a shirt, blouse, T-shirt, or other top, but sometimes next to the skin. Sweaters were traditionally made from wool, but can now be made of cotton, synthetic fibers, or any combination thereof. Sweaters are maintained by washing or dry cleaning, and the use of a lint roller or pill razor.
Hoodie
A hoodie (also called a hooded sweatshirt, hooded jumper or hoody) is a sweatshirt with a hood. Hoodies often include a muff sewn onto the lower front, and (usually) a drawstring to adjust the hood opening.
Sweater (noun)
A knitted jacket or jersey, usually of thick wool, worn by athletes before or after exercise.
Sweater (noun)
A similar warmth.
Sweater (noun)
One who sweats (produces sweat).
Sweater (noun)
One who or that which causes to sweat.
Sweater (noun)
A diaphoretic remedy.
Sweater (noun)
One who sweats coins, i.e. removes small portions by shaking them.
Hoodie (noun)
A sweatshirt, with an integral hood and, sometimes, a large kangaroo pocket at the front.
Hoodie (noun)
A young person wearing such a sweatshirt, usually a male.
Hoodie (noun)
Foreskin.