Did you know that "monger" means trader (fish monger, iron monger, cheese monger) and there's little explanation for why monger drifted into the pejorative (war monger, gossip monger, etc). Did you know that grocer goes all the way back to ancient Rome and refers to someone who sells in bulk, i.e. by the gross? Oh, and here's a fun fact: "meat" used to apply to all food types. What we know as meat was "flesh meat," veggies, "green meat," and dairy was "white meat."
This latest RobWords video looks at these and many other job title etymologies.