This is the 202nd most frequent German word.
lässt
"Lässt" is the 3rd person singular present tense form of "lassen," meaning "allows," "lets," or "leaves."
Here, 'lässt' is used in the context of allowing or permitting someone to do something.
Er lässt mich das Buch lesen.
He lets me read the book.
Here, 'lässt' is used to indicate allowing an action to happen, specifically letting go or releasing something.
Sie lässt den Ball fallen.
She lets the ball drop.
In this case, 'lässt' is used figuratively to mean causing or leading to a state or action, in this case, thinking.