This is the 5226th most frequent Japanese word.
面白かっ
"面白かっ" is the stem of "面白かった," meaning "was interesting" or "was fun."
In this sentence, "面白かった" is used as the past tense of the adjective "面白い," meaning "interesting" or "fun," to describe the quality of the movie.
昨日見た映画は本当に面白かったです。
The movie I watched yesterday was really interesting.
Here, "面白かった" is used to express that the story captured interest or was amusing, showing admiration for its content in past tense.
その話はとても面白かったけれど、少し難しかったです。
That story was very interesting, but a bit difficult.
In this context, "面白かった" conveys the enjoyment experienced during an activity, providing a full past tense reflection on the action.