A person who prefers outdoor activities (camping, hiking, fishing, etc.); an 'outdoor type'.
週末はアウトドア派の友達とキャンプに行く。
On weekends I go camping with my outdoorsy friends.
彼女はアウトドア派で、ハイキングや釣りが好きだ。
She is an outdoor person and likes hiking and fishing.
アウトドア派とインドア派で旅行の予定が合わなくて困った。
We had trouble planning the trip because the outdoorsy people and the indoor people couldn't agree.