Wiktionary defines a hobby as
An activity that one enjoys doing in one's spare time.
Other dictionaries tend to have similar definitions.
Some people believe that the word hobby can be used for any regularly practiced leisure activity, such as watching TV, or listening to music.
On the other hand, others believe use of the word is not appropriate for passive activities such as watching TV. If watching TV were a hobby, one could argue that watching the wall could also be technically a hobby.
Also, by Wiktionary's definition, having sex would fall under 'hobby'. It is not commonplace to refer to having sex as a hobby so another logical criterion to refer to something by the word 'hobby' could be that the activity (or interest in it) should not be too universal.
So, what constitutes correct usage of the word 'hobby'?
Does any pastime (watching TV, having sex...) qualify to be called a hobby or are there one or more criteria such as:
- Shouldn't be too universal
- Shouldn't be a passive activity
- Should be a productive or developmental activity
Edit: Please let us not get carried away with sex-related jokes and discussions but focus on the definition of the word hobby