Difference between Concerned and Preoccupied

CONCERNED vs PREOCCUPIED: ADJECTIVE

Deeply absorbed in thought
Absorbed in thought; engrossed.
Excessively concerned with something; distracted.
Formerly or already occupied.
Already used and therefore unavailable for further use. Used of taxonomic names.
Concerned with something else; distracted; giving one's attention elsewhere.
Having or showing excessive or compulsive concern with something

Having or manifesting disquietude; uneasy; troubled; anxious: as, she watched his movements with a concerned look or feeling; he was concerned about his prospects.
A euphemism for damned.

In zoology and botany, already used as a name for a genus, species, etc., and therefore, by the laws of priority, rejected for any other genus, species, etc., to which it has been applied.
Occupied previously; engrossed; hence, lost in thought; meditative; abstracted.

Worry, Apprehensive, Alarmed, Worried, Taken up, Related to, Haunted, Related, Implicated, Solicitous, Involved, Obsessed, Preoccupied, Interested, Afraid

Disturbed, Alarmed, Fascinated, Perturbed, Disquieted, Worried, Distracted, Deep in thought, Taken up, Thoughtful, Lost, Haunted, Bemused, Concerned, Obsessed

Worrying, Worry, Apprehensive, Alarmed, Worried, Related to, Haunted, Related, Implicated, Solicitous, Involved, Obsessed, Preoccupied, Interested, Afraid

Concentrated, Disturbed, Alarmed, Fascinated, Perturbed, Disquieted, Worried, Distracted, Deep in thought, Thoughtful, Lost, Haunted, Bemused, Concerned, Obsessed

In these alone, were the whole people concerned.
Is that something we should be concerned about?
The Cherokees had every reason to be concerned.
This chapter is concerned only with market regulation.
All skin types, especially those concerned with ageing.
They re concerned how it will affect that.
The name of the concerned lot plan, if any, and the lot numbers of the concerned and abutting properties.
Brook was less concerned with realism, and more concerned with translating the play into a form that could communicate with the modern world.
This enterprise is most suitable when national security is concerned as it is under the direct control and supervision of the concerned Ministry.
We are less concerned with finding texts, and more concerned with stopping the flood of texts coming in.

Patsy, that may have been preoccupied with work.
But I am much more preoccupied with loving.
Often we are too preoccupied to pay attention.
Not only that, I was preoccupied with self.
They said he looked well but very preoccupied.
''Suddenly they become preoccupied with neatness he said.
India preoccupied with problems in its immediate neighbourhood.
Germans appear to be preoccupied with such themes.
Whereas lovers are both preoccupied with each other, friends are both preoccupied with the same things.
Our era is entirely preoccupied with little things which are to no purpose, or rather it is entirely preoccupied in the service of money.