1.Definition: capable of being influenced or formed

"The plastic minds of children"

Related Adjective(s):pliant

2.Definition: capable of being molded or modeled (especially of earth or clay or other soft material)

"Plastic substances such as wax or clay"

Related Adjective(s):fictile, moldable

3.Definition: forming or capable of forming or molding or fashioning

"The plastic forces of nature"

Related Adjective(s):formative, shaping