Negative Magic

Curses is the effective action of some power, distinguished solely by the quality of adversity that it brings. It is also said to result from imprecation or execration, or other imposition by magic or witch craft asking or commanding natural force, or spirit bring misfortune to someone. 

Unlike Jinxes or Hexes, Curses cause greater intensity when the caster inflicted upon it on its target. Generally, it is more harmful, usually inflicts control over the individual and creates much terror over others. These kinds of magic spells are commonly used during duels or during life-or-death situations.

The types of Curses also varies, mostly depending on its magnitude and on the wizard/caster's ability to produce it. Some can be easily done even when the person only learned it at that time and some which usually takes a while for the person to finally be able to do or control it.

Generally, Curses are said to be evil that causes harm or destruction to the individual, but just like the other forms of Negative Magic, it can also serve as some sort of defense magic when faced in an unlikely situation.

Restricted Curses:

FIENDFYRE  or the Cursed Fire - it is an irrepressible flame that takes the shape of a variety of creatures (from lions to phoenix) that appear to stalk or hunt those caught in its path. On the other hand, it is also known to destroy Horcruxes. Incantation: Fiendfyre

MORSMODRE - it is the incantation used to conjure the Dark Mark, which had been used by the Death Eaters themselves. It comes from the Latin mors, "death" and mordere, meaning "to bite". Incantation: Morsmodre

Other Curses: 

ANTONIN DOLOHOV'S CURSE - It causes severe internal injury which potentially lethal through a sudden slash of wand movement that causes  purple flames to strike the target. Incantation: Flamma Incidere

ANTI-DISAPPARITION JINX - It used to prevent Disapparition in an area for a time. Presumably can be used to prevent a victim from entering a defended area, or be used to trap a victim in an area. Incantation: Nullevanesco

BLASTING CURSE - It causes anything that the spell comes into contact with to explode. It comes form the latin word confringo "I break".  Incantation: Confringo

GEMINO CURSE  - when touched, will duplicate into many useless copies to hide the original and the duplicates will be hot enough to burn skin.  Incantation: Gemino Exuro 

LEG-LOCKER CURSE -  it is a spell that causes the victim's legs to lock together. It comes from the latin locomotor meaning mobilise, and meaning death; taken together it means "death of motion". Incantation: Locomotor mortis

LEGILIMENCY - it is the act of navigating through the many layers of a person's mind and correctly interpreting one's finding. Advanced Legilimens doesn't need to use the incantation, but rather cast it non-verbally, which gives a much better effect. The opposite of Legilimency is OCCLUMENCY.    Incantation: Legilimens                                                                                                       

OPPUGNO - literally means "to attack". It causes conjured creatures under the control of the caster to attack the target or victim. Incantation: Oppugno

SECTUMSEMPRA - It acts as an invisible sword, slashing the target as a sword would. It comes from the latin word "sectum" meaning having been cut and  "semper" meaning always. Incantation: Sectumsempra

TABOO -  it designates a word as a key to revealing the speaker's location. This curse controls individuals by limiting their freedom to speak, and thus causes great stress, terror, and frustration. Incantation: Taboo

TONGUE TYING CURSE -  A curse which prevents certain information from being revealed by the individual upon whom the spell is placed. The curse manifests itself by causing the tongue to temporarily curl backwards upon itself. Incantation: Lingua Ligo 

* Legend: Curses in green can be done by 4th years and up only, which is under the Handbook of Spells by the Hogwarts Online Board. Curses in orange can only be done by 6th years and up. Restricted curses aren't allowed to be done by any wizard, or they will be castigated by the Ministry of Magic Laws. They are only for theoretical study purposes only.