This is the 7986th most frequent Dutch word.
ergerlijk
Annoying or irritating.
In this sentence, "ergerlijk" is used as an adjective to describe the situation of constant tardiness as being irritating.
Het is echt ergerlijk hoe vaak hij te laat komt.
It is really annoying how often he is late.
Here, "ergerlijk" modifies "gedrag" to specify the character of the behavior that causes irritation to others.
Zijn ergerlijk gedrag irriteert iedereen op kantoor.
His annoying behavior irritates everyone in the office.
The word "ergerlijk" in this sentence is applied to express a personal opinion about the untidiness of a location, highlighting an emotional reaction of annoyance.