Yüzme çok eğlencelidir.
English: Swimming is very fun.
In Turkish, 'isim-fiil yapıları' (verbal nouns or infinitives) are verb forms that act like nouns. They are created by adding certain suffixes to verb stems.
You use these forms when you want to talk about an action as a thing or idea, not as something someone does. For example, to talk about 'reading' as an activity, not about someone reading.
Yüzme çok eğlencelidir.
English: Swimming is very fun.
Kitap okumak önemlidir.
English: Reading books is important.
Yazmak benim hobimdir.
English: Writing is my hobby.
Toplantıya gelme kararı aldık.
English: We decided not to come to the meeting.