The o is like the o in hot, got, and not. And the following u sounds like the u in put and pull. The s is pronounced like the z in zoo, zip and zap, and the final a is like the a in China. The stress is on the first syllable om.
An ombudsman is someone who investigates complaints made by people against the government or any public organization. He is an independent official who represents the common man in his fight against the government.
• All complaints must be made in writing to the banking ombudsman by three this afternoon.
The word is Swedish in origins and it means representative or agent. I understand that the word was borrowed into English in the 1960s. The word is being slowly replaced by ombudsperson.