"His performance is honest" - Huh?

Sometimes I think that movie reviewers are wannabe wine connoisseurs. They grasp for descriptive terms that sound meaningful but are, in fact, vacuous. Take this review of War of the Worlds. The reviewer says of Tom Cruise, " His performance is honest and wrought with emotional content."

What does it mean for a performance to be “honest”? Can anybody tell me what that means? And does it imply that an actor can give a dishonest performance? Can anyone give me an example of a dishonest performance?

By “honest,” I think reviewers mean that a perfomance is not mannered or hokey. A “dishonest” performance would be hammy and unbelievable.

Compare “acting the truth.”

By definition, acting is not truth – but when people say this, they’re talking about emotional truth.

“YOU CAN’T ACT THE TRUTH!”

As Lillian Gish used to say, “Never let them catch you ‘acting.’”

Ok, that makes sense, I guess, thanks. Why can’t they just say, “His performance was very believable”, so that ordinary people like me can understand what they mean?

I take an ‘honest’ performance to be a very open one. With acting, it perhaps exposes more of the character and/or of the actor than might otherwise occur. But yes, it can be a vague term to use in times of creative block when writing reviews.