1.
straight, directly
In a direct line without curves or turns. Can describe physical direction or going somewhere without detours.
2.
upright, honest
Describing a person's character as straightforward and honest.
まっすぐ describes something straight (without curves) or someone honest and direct.
Forms
Physical meaning
Figurative meaning
Writing
Can be written 真っ直ぐ, but hiragana is standard.
Related Words
Compare:
曲がる (to turn, to bend)
Synonym:
正直 (honest, frank (sense 2))
Compare:
斜め (diagonal, slanted)