couch potato

Definitions

General English

  • noun a person who sits watching TV or videos all day

Slang

  • noun a lazy, greedy person. This expression from the late 1980s describes a person whose only activity is to lie in front of a television and eat and drink. (‘Couch’ is an American synonym for sofa.).

Idiom of “couch potato”

inactive person who spends a lot of time watching television
http://www.dictionarycentral.com/definition/couch-potato.html