This is the 12443rd most frequent Polish word.
nadawał
"Was giving," "was sending," or "was suitable (for)" depending on context.
The verb 'nadawał' indicates suitability or appropriateness for something.
On nadawał się do tej pracy.
He suited this job.
Here, 'nadawał' refers to the adequacy or readiness of the letter for a certain purpose, sending.
List nadawał się na wysłanie.
The letter was suitable for sending.
In this sentence, 'nadawał' functions as 'gave,' indicating the provision of a quality or characteristic to something.