famous OR infamous?

These two adjectives have rather different meanings, and different pronunciations. In simple terms, the difference is:

famous = well-known

infamous = well-known for something bad

If somebody is famous, then many people know about that person. Here are some famous people. You probably know all or most of them:

Notice that famous people can be good or bad. Famous does not "judge" people. It is just a statement that somebody is well-known.

Famous is objective (a matter of fact). Infamous is subjective (it tells you about the speaker's opinion).

If somebody is infamous, then many people know about that person because he did something bad. He has a "bad reputation".

Look at these example sentences:

Notice that famous can describe people or things; but infamous is usually used for people.

Pronunciation

In both words the stress is on the first syllable, which means that they sound very different.

famous FA-mous /ˈfeɪməs/

infamous IN-fa-mous /ˈɪnfəməs/