When a person is being forthright, they're being direct, clear, or even straight-up. The opposite of forthright might be evasive, shifty, indirect, or circuitous.

What is a forthright person?

going straight to the point; frank; direct; outspoken: It's sometimes difficult to be forthright and not give offense. proceeding in a straight course; direct; straightforward: a forthright glance.

Is forthright a compliment?

If you describe someone as forthright, you admire them because they show clearly and strongly what they think and feel.