Something that grows or lives without any assistance from human beings is "wild." You can use this adjective to describe trees, plants, animals, insects, and–sometimes–people.
We found some wild berries growing in a field.
Be careful when you walk in the forest. You might come across a wild animal.
You don’t see very many wild animals when you live in a city.
It was interesting to see so many alligators living in the wild when we visited Florida. ("the wild" functions as a noun in this sentence.)
A lot of interesting weeds grow wild in our backyard.
The word "wilderness" is similar to "wild."
Wolves are found in wilderness areas.
They live in the wilderness.
wolf
You can use "wild" to describe a person or describe your personal feelings about something:
She has kind of a wild personality. At parties she does a lot of crazy things.
The kids down the street are a little wild. Their parents let them do whatever they want.
Teenage girls are wild about the singing group, One Direction.
I’m not wild about this new design for the website. (not wild about = dislike)
Bert says his new girlfriend, Jennifer, drives him wild. (drive one wild = to cause intense feelings of pleasure)