The crossword solution for the term UPSET (AT) is SORE (4 letters). The term 'UPSET' is an adjective that describes a feeling of distress, agitation, or anxiety. It can also refer to a state of being emotionally disturbed or disordered. The term 'SORE' is an adjective that describes a physical pain or discomfort, usually in the body. It can also refer to a feeling of emotional distress or hurt. Therefore, the crossword solution for the term UPSET (AT) is SORE (4 letters), as both words describe a feeling of distress or hurt.