This is the 5554th most frequent Russian word.
понадобится
"Понадобится" means "will be needed" or "will be necessary."
Here, 'понадобится' is used in its future tense, third person singular form to indicate that help is needed in the future.
Мне понадобится помощь.
I will need help.
In this conditional sentence, 'понадобится' is used to express a hypothetical need for a book.
Если тебе понадобится книга, скажи мне.
If you need the book, tell me.
This sentence uses 'понадобится' in the future tense with negation, indicating that more time will not be necessary.