also: うおっちんぐ
Loanword from English 'watching', often used in compounds like バードウォッチング (birdwatching) or 人間ウォッチング (people-watching).
I enjoyed birdwatching at the park on the weekend.
カフェで人間ウォッチングするのが好きだ。
I like people-watching at cafes.
I enjoy stargazing on the weekends.