Not changing oil, I'm not coming home for starters, having broken down (10)

I believe the answer is:

monolithic

I'm a little stuck... Click here to teach me more about this clue!

But I can't explain it at all! Could you help me understand?

(Another definition for monolithic that I've seen is " Immovably massive".)

I've seen this clue in The Everyman puzzle in The Observer.

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