This is the 18th most frequent Hebrew word.
אך
"אך" means "only" or "however," depending on context.
The word 'אך' here is used as a conjunction meaning 'but,' introducing a contrasting idea.
הוא רצה לשחק בחוץ, אך החל לרדת גשם.
He wanted to play outside, but it started to rain.
In this sentence, 'אך' introduces a nuance that adds a slight contradiction or limitation to the previous statement.
הספר היה מעניין, אך מעט ארוך מדי.
The book was interesting, albeit a bit too long.
Here 'אך' is used to indicate a contrast between the speaker's acknowledgment and their intellectual or emotional position.