Usage patterns
〈場所〉をまっすぐ行くto go straight along a place (e.g. road)
If you go straight along this road, you'll reach the station.
〈人〉の目をまっすぐ見るto look someone straight in the eye
He spoke while looking me straight in the eye.
まっすぐな性格a straightforward, honest personality
She has a straightforward personality and is trusted by everyone.
まっすぐに立つto stand upright/straight
Please straighten your back and stand up straight.