Questions & Answers about Keine Ahnung, warum er nicht kommt.
Why do we use Keine instead of Nicht here?
Where is the verb in the first part, Keine Ahnung?
This is a conversational shortcut, just like saying no idea in English. The full grammatical phrase is Ich habe keine Ahnung (I have no idea). Germans frequently drop the Ich habe in everyday speech.
Why is the verb kommt at the very end of the sentence?
The word warum (why) starts a dependent sentence, known as a subordinate clause. In German, whenever you use a subordinate clause, the acting verb (kommt) is always pushed to the very end of that clause.
Why does nicht come immediately before kommt?
In a subordinate clause where the verb sits at the end, the negation word nicht usually goes right before that verb to directly negate the action.