Here are some examples:
* Workaholic: Someone who is addicted to working.
* Shopaholic: Someone who is addicted to shopping.
* Chocaholic: Someone who is addicted to chocolate.
* Alcoholic: Someone who is addicted to alcohol.
So, if you see a word ending in "holic," you can usually assume that it refers to someone who is obsessed with or addicted to something.