someone who watches a lot of television, eats junk food and takes little or no physical exercise – informal
Couch potato was a humorous American coinage using the image of a person with the physical shape of a potato slouching on a sofa or couch. Originally, the phrase relied on a pun with tuber in the slang term boob tuber which referred to someone devoted to watching the boob tube or television.
Related Idioms :
on the couch
undergoing psychoanalysis or psychiatric treatment