To consider to be very worthy, valuable, or important; to esteem highly. The phrase think much of is usually used in negative sentences.
Father didn't think much of Paul's idea of buying a goat to save lawn mowing.
I don't think much of him as a baseball player; he's a slow runner and a poor hitter.
James thinks highly of his new boss, who is a kind and helpful person.
Mary thinks a great deal of Tim.
The teacher thought a lot of Joe's project.