addict phoneticPhoneticPhoneticPhoneticPhoneticPhoneticPhoneticPhoneticphonetic noun [C] 

1. a person who cannot stop doing or using something, esp. something harmful
 

   a drug/heroin/nicotine
addict
    a gambling addict.
    HUMOROUS I'm a chocolate/television/shopping addict.

addicted phoneticPhoneticPhoneticPhoneticPhoneticPhoneticPhoneticPhoneticPhoneticPhoneticphonetic adjective 
   
   She was
addicted to heroin at the age of 14.
    I'm addicted to (=I very often eat/drink) chocolate/vodka.
    She's become addicted to love stories/horror films/football.
    I know that if I start watching a soap opera I immediately become hopelessly addicted.

addiction phoneticPhoneticPhoneticPhoneticPhoneticPhoneticPhoneticPhoneticPhoneticPhoneticphonetic noun 
  
   Her previous novel dealt with her recovery from drug
addiction. [U]
    For years she was dependent on drugs and drink and it was only in her fifties that she finally    
   managed to overcome these
addictions. [C]
    Patrick is trying to cure himself of his addiction to alcohol. [U]

addictive phoneticPhoneticPhoneticPhoneticPhoneticPhoneticPhoneticPhoneticPhoneticPhoneticphonetic adjective 

1. An addictive drug is one which you cannot stop taking once you have started.
 

   Narcotics such as morphine, heroin and cocaine are extremely
addictive.
    Tobacco is highly addictive and the tobacco industry knows this.

2. Addictive is also used of any activity or food that you cannot stop doing or eating once you have 
    started.
 

   The problem with video games is that they're
addictive.
   These nuts are addictive - I can't stop eating them!

3. Someone who is described as having an addictive personality very quickly becomes addicted to 
    drugs, activities or food.
 

This page is cited from Cambridge Dictionaries Online.  For the original, please visit
http://dictionary.cambridge.org/define.asp?key=addict*1+0