What is the Meaning & Definition of inert

That of life, mobility and full of futility

The term inert is used to refer to that which is characterized by the lack of life, mobility or by its uselessness. "The hands of the members of the expedition were inert as a result of the intense cold that passed while they were lost".
Then, when something is inert it is because it is lacking life or reaction to a stimulus. The concept is normally linked to the inefficiency and immobility and can be applied in various fields just to express those ideas.
If a body is inert it will be movement and that may be due to a faint, that it is an issue that can be changed, i.e., the body can recover mobility after an animation, or by inertia may be caused by death.

Unproductive people

On the other hand, the concept is recursively applied to those people who are characterized by unproductive, useless, lacking in efficiency negligent behaviour and therefore characterized by inefficiency.
So that when shown to a person who does not like to work or perform any other activity that involves commitment to action, movement, in order to achieve a goal or purpose, can be described in terms of inert.

The other side is the action

The other side of course will be the active person, showing effective and diligent in their behavior and performance.
The above shows that arise inert is a feature that will be assessed as negative in contexts where it is demanded action and willingness to act. And therefore if you search for an active profile, who is shown inert it will not be taken into account for the work.

Biology: things have no own mobility

In biology will be called inert to all those things which do not present mobility if same. The rocks, for example, are considered inert bodies.

Anti social person

On the other hand, when a person shows no emotion of any kind in his life and more than nothing is abstracted from everything that surrounds it, without participating in talks, relations, among other things, they say that such or which remains inert to the emotions and feelings of life.
We are able to define something as inert matter when the organizational level that presents is well below the levels of organization residing on the contrary if it presents the matter; the stone is composed of elementary particles, type atoms, molecules, but without presenting organelles.

Chemistry: body that follows no action even combined with other

And at the behest of the chemistry, the term inert is used to refer to that body that stays idle even having been combined with another, such is the case of inert gas.
Because an inert gas, also known as noble gas is a type of gas not reactive under certain conditions of chemical work on it. Most well-known and popular inert gases are nitrogen and noble gases.
For example, in the case of nitrogen this it is difficult to react at room temperature, will always be necessary a high temperature to make it.
This type of gas are used mostly in some chemical reactions in which turns out to be necessary to override the presence of a reactive gas; the oxygen in some welding processes.