This is the 10076th most frequent French word.
grincheux
Grumpy; irritable.
Here, 'grincheux' is used as an adjective describing someone's mood in the morning.
Il est souvent grincheux le matin avant de prendre son café.
He is often grumpy in the morning before having his coffee.
In this example, 'grincheux' describes a typical behavior or attitude of colleagues that can affect collaboration.
Je n'aime pas travailler avec des collègues grincheux.
I don't like working with grumpy colleagues.
It illustrates the temporary state of irritability of children due to fatigue, with 'grincheux' used as a descriptive adjective.