This is the 7402nd most frequent Dutch word.
boe
An exclamation used to mimic the sound of a cow or to express surprise or fright ("boo").
The word 'boe' is used as an interjection to express surprise or fright, often used to startle someone.
Toen hij schrok, riep hij ineens 'boe!' naar mij.
When he was startled, he suddenly exclaimed 'boo!' at me.
Here, 'boe' represents the sound that cows typically make, equivalent to 'moo' in English, used in an onomatopoeic sense.
De koe in het weiland zei 'boe' tegen de kinderen.
The cow in the meadow said 'moo' to the children.
In this usage, 'boe' is again an interjection, used in a playful or entertaining manner, often for comedic effect.