Here is a definition of Adventure game from Wikipedia
Essential elements of the genre include storytelling, exploration, and puzzle-solving. Marek Bronstring, former head of content at Sega has characterised adventure games as puzzles embedded in a narrative framework; such games may involve narrative content that a player unlocks piece by piece over time. While the puzzles that players encounter through the story can be arbitrary, those that do not pull the player out of the narrative are considered examples of good design.
Combat and action challenges are limited or absent in adventure games; this distinguishes them from action games. In the book Andrew Rollings and Ernest Adams on Game Design, the authors state that "this [reduced emphasis on combat] doesn't mean that there is no conflict in adventure games ... only that combat is not the primary activity." Some adventure games will include a minigame from another video-game genre, which adventure-game purists do not always appreciate.