What exactly are psychic abilities?

Certainly everyone knows about psychic abilities, but to know and understand exactly abiut it is also not clear understanding , following I will provide some information to help you understand clearly and in greater detail:

Psychic abilities, also known as ESP (Extra-sensory Perception), are categorized by an individual's ability to draw conclusions from people, places or things by obtaining information other than the "5 known senses". Psychokinesis is also considered a psychic ability, which involves the manipulation of external forces using nothing but your mind, (Telekinesis, Hydrokinesis, Aerokinesis). 

• Clairvoyance is obtaining information through psychic visions; "clear-seeing" 

• Clairaudience is obtaining information through hearing psychic messages; "clear-hearing"

• Clairsentience is obtaining information through feeling energy; "clear-feeling" 

• Claircognizance can be closely related to basic intuition, and is a person's ability to "just know" when to do something; "clear-knowing" 

• Telepathy is the ability to communicate with other people, animals or plants using only your mind. 

• Remote viewing is the ability to see through your mind's eye a location separate from where you are.

• Astral travel/ Astral projection is the ability to place your consciousness outside of your body and explore your surroundings on what is called the "Astral plane". 

• Lucid dreaming was once considered to be a psychic ability, but has since been proven to exist. 

• Channeling/ mediumship is a person's ability to communicate with spirits.

There are hundreds of different abilities that could realistically be considered psychic/ paranormal. 
The ones I have listed are just a few of the main ones. :)
Besides, "psychic ability" is also defined as the ability to sense probabilities, distant events, nonphysical realities, or the memes and thought-forms of the mass consciousness without the use of conscious, rational, linear processes. Psychic ability does not necessarily spring from any supernatural cause. It can be viewed as a heightened form of pattern recognition. A NASA scientist of my acquaintance once defined "intelligence" as "the ability to see connections amongst apparently unrelated phenomena;" that definition could be used for "psychic ability" as well.