左(zuǒ) - left, the left-hand side in Mandarin

左 (zuǒ) is the character for left, but it rarely stands alone as a place. To say something is on the left you almost always need a suffix: 左边 (zuǒ biān) or 左面 (zuǒ miàn) for the left side, 左手 for the left hand, 左脚 for the left foot.

Bare 左 belongs with verbs of direction and with fixed pairs. 往左 and 向左 mean towards the left, 左转 is to turn left, and 左右 means the two sides together, which is also the ordinary way to say approximately: 三十岁左右 is about thirty years old.

The trap is political. Chinese borrowed the left and right of European politics directly, so 左 also means left wing, and in a Chinese context that history is loaded in ways an English reader will not expect. Nothing goes wrong when you are giving directions, but 他很左 is a comment about politics, not about handedness.