This is the 616th most frequent Croatian word.
trebati
"To need" or "to have to."
Here, 'trebati' is used in its subjunctive form ('trebala bi') to express a suggestion or recommendation.
Trebala bi pročitati ovu knjigu.
You should read this book.
In this sentence, 'trebati' is conjugated to match the first person singular subject and means 'to need'.
Trebam tvoju pomoć.
I need your help.
In this usage, 'trebati' functions to indicate something necessary or inevitable, conjugated in past tense.