This is the 746th most frequent German word.
warnt
"Warnt" means "warns" in English.
In this instance, 'warnt' highlights a habitual action where the subject issues warnings under specific conditions.
Er warnt immer vor Stürmen, wenn das Wetter schlecht wird.
He always warns about storms when the weather becomes bad.
Here, 'warnt' describes the sign's purpose of providing caution to those who see it.
Das Schild warnt vor einer rutschigen Straße.
The sign warns about a slippery road.
Here, 'warnt' is used as a verb in the present tense to indicate that the teacher (subject) is alerting the students to something.