This is the 195th most frequent Estonian word.
pidi
"Pidí" means "had to" or "was supposed to" in English.
In this context, pidi shows a completed necessity or past obligation.
Ta pidi selle raamatu laenutama raamatukogust.
He/She had to borrow this book from the library.
Pidi is used here to indicate necessity, implying an obligation to perform an action.
Ma pidi eile sõbrale helistama.
I had to call my friend yesterday.
Here, pidi suggests a logical conjecture or assumption in the past.