This is the 15846th most frequent Turkish word.
tutmasam
"If I don't hold."
Here, 'tutmasam' is used in a conditional clause to express a potential undesired outcome of not holding the string.
Eğer ipi tutmasam, balon uçar.
If I don't hold the string, the balloon will fly away.
In this case, 'tutmasam' is illustrating an unreal past conditional situation.
Kitabı tutmasam yere düşecekti.
If I hadn't held the book, it would have fallen.
Here, 'tutmasam' indicates a preventative action in conditional mood to avoid a negative consequence.