considerable, deep, grave, great, serious
growing, mounting
genuine
He demonstrated genuine concern for others.

general, widespread
national, public
public concern about increased taxes

particular
There is particular concern about the use of pesticides.

feel
He felt some concern for her safety.

articulate, express, show, voice
arouse, cause, heighten
The lack of firefighting equipment has caused concern.

allay, alleviate, assuage, ease
appreciate, understand
cite, echo
He cited public concern over airport security.

dismiss

in sb's concern
She forgot her own worries in her concern for him.

out of concern
concern about, concern over
She expressed her deep concern about conditions at the factory.

concern for
Out of concern for her health, we suggested she take a week off work.

be of (no) concern to sb
Increased use of drugs is of great concern to parents.

(a) cause for concern
The president's health is giving serious cause for concern.

a lack of concern
I was surprised by her lack of concern.

a matter of concern
Stress at work is a matter of concern to staff and management.

chief, main, major, overriding, paramount, primary
What are your main concerns as a writer?

common
a common concern for new parents

pressing, serious
I have other, more pressing concerns.

legitimate, valid
environmental, ethical, privacy, safety, security
This new technology brings with it security concerns.

outweigh, override
Practical necessity overrides any other concerns.

be none of sb's concern
How much we paid is none of your concern.

directly
mainly, mostly
The letter is for both of us, but it mainly concerns you.

in
Everyone who was directly concerned in (= had some responsibility for) the incident has now resigned.

a lot, greatly, really
It really concerns me that he doesn't eat properly.

slightly

Concern is used with these nouns as the subject:
complaint, dispute, document, hypothesis, proposition, report, story, study, tale