Kafka style 80’ novel - office setting w/violent ending

[Robin]

I read the book in my 20’s sometime in the 80’s old paperback novel. I believe a cryptic one word title referring to the Business , Agency or similar. A man is hired at an office that in fact gives busywork to dangerous people or men, to keep them from committing harm in the community. He catches in that the work is nonsense and flees. He is chased a wild eyed man catches up to him , reaches into his car and cuts off his hand— then leaves him with a last verbal and mysterious warning!

I can’t recall much except at the novel start he has trouble getting work it effects his marriage he is happy to get the office job.
We see in the office dull eyed workers where the work is boring and never ending. He becomes one of them, then figures out the work is all meaningless and he flees , but the “ bosses” realize he KNOWS, and send out the man to teach him a lesson, to keep him quiet. The novel ends with the warning given!