Usage of "inquieto"
How do one use the word "inquieto"? As I have understood it, it can mean:

1) 'worried', and it is then used together with 'estar' and typically placed after the noun it refers to.
Ex. Estoy inquieta. El chico inquieto no quiere hacer el examen.

2) 'enterprising', and is then used together with 'ser'. Is it typically placed after the noun too? And in that case, do you have to understand that one mean 'enterprising' and not 'worried' from the context?

3) 'lively', and is the used together with 'ser' and is placed *before* the noun.
Ex. Tengo un inquieto perro.

4) 'restless'. Is this used together with 'ser' and is also placed before the noun? Do one say: Tengo las inquietas piernas?

Question

Usage of "inquieto"
How do one use the word "inquieto"? As I have understood it, it can mean:

1) 'worried', and it is then used together with 'estar' and typically placed after the noun it refers to.
Ex. Estoy inquieta. El chico inquieto no quiere hacer el examen.

2) 'enterprising', and is then used together with 'ser'. Is it typically placed after the noun too? And in that case, do you have to understand that one mean 'enterprising' and not 'worried' from the context?

3) 'lively', and is the used together with 'ser' and is placed *before* the noun. 
Ex. Tengo un inquieto perro.

4) 'restless'. Is this used together with 'ser' and is also placed before the noun? Do one say: Tengo las inquietas piernas?

Answer

Inquieto is related with state nervous, action( moviment). For example if you say : Estoy inquieto (means that something disturb you, you are nervous for something)
If you use the verb ser: Soy una persona inquieta siempre estoy estudiando ( you means that you are always are in continous moviment (fisic or non fisic). In this example you say that always need to learn.

Maybe I don't explain me very well, in this case feel free to send me a mail.  Bye

Answer

Although Spanish is less strict than English when it comes to word order, we normally place the adjectives after the nouns. If you change the "normal" order, the word out of place gets extra emphasis.

I don't know who told you that "inquieto" has different preferred positions depending on its meaning, but that's simply not true. The meaning varies depending on the context.

Tengo un perro inquieto is the most common order. If you say "Tengo un inquieto perro", it sounds a bit strange, although it is grammatically correct.

Answer

"estar inquieto/a"
is an expression used to say that you're expecting something and you can't wait or something is disturbing you, like being anxious.
is also used when somebody has a lot of energy and you can't stop him.
"este niño es muy inquieto"

Answer

have a look at this link... you will be able to see the differents uses of "inquieto"
http://www.wordreference.com/es/en/translation.asp?spen=inquieto

Answer

"Inquieto " es un adjetivo calificativo, o sea que expresa una cualidad del sujeto, y tiene entre otros los siguientes significados: Restless, worried, thoughtful,  impatient,  hesitant, uncertain, restless,  anxious, fearful, troubled, afraid, shaky, pessimistic.
Ej: Es un niño muy inquieto.  Estoy inquieto por la noticia recibida.