Worried or anxious about something.
“I am concerned about the noise levels in the building after 10 p.m.”
“Several residents are concerned that the new policy will increase parking fees.”
This word is common in inquiry or complaint letters, as in 'I am concerned about the noise levels.' It usually points directly to the main issue being raised, which is helpful when answering the 'what is the writer's main concern' type of question.
Synonyms: worried, troubled, anxious