My definition of adventure is doing something that makes you uncomfortable but will ultimately produce growth.
For example, starting a business is an adventure - a trek into unknown territory. Writing a book or taking up painting can be an adventure. Learning to dance the tango, or travelling to Brazil? Both adventurous, wouldn't you say?
The important thing is to do what you are interested in doing and don't allow fear or naysayers to stop you. Life can be an adventure to a boring string of miserable days. The choice is yours.