General worry or anxiety:
* Worried: This is the most straightforward synonym for "concerned" when it refers to a general feeling of worry or anxiety.
* Apprehensive: This suggests a stronger sense of unease or fear about something potentially bad happening.
* Anxious: This emphasizes a feeling of nervousness or worry, often accompanied by physical symptoms.
* Troubled: This implies a sense of sadness or distress about something.
Specific interest or involvement:
* Interested: This emphasizes a desire to learn more or be involved in something.
* Involved: This suggests a direct connection or participation in something.
* Engaged: This emphasizes active participation and commitment to something.
* Committed: This implies a strong sense of dedication and responsibility.
Regarding a specific issue or person:
* Preoccupied: This suggests that someone is thinking about something a lot, to the exclusion of other things.
* Focused: This emphasizes a strong concentration on something.
* Attentive: This suggests a careful and thoughtful focus on something.
* Sympathetic: This implies a sense of understanding and compassion for someone's situation.
Formal alternatives:
* Solicitous: This is a more formal synonym for "concerned" and suggests a desire to help someone.
* Alarmed: This emphasizes a sense of shock or fear.
* Distressed: This suggests a strong sense of sadness or anxiety.
The best synonym for "concerned" will depend on the specific context and the meaning you want to convey.