Malingering is the fabrication, feigning, or exaggeration of physical or psychological symptoms designed to achieve a desired outcome, such as relief from duty or work, avoiding arrest, receiving medication, and mitigating prison sentencing.

Although malingering is not a medical diagnosis, it may be recorded as a "focus of clinical attention" or a "reason for contact with health services". It is coded by both the ICD-10 and DSM-5. Malingerers do not always act with malicious intent. For example, the homeless may fake a mental illness to gain hospital admission. Impacts of failure to detect malingering are extensive, impacting insurance industries, healthcare systems, public safety, and veterans’ disability benefits. Malingered behaviour typically ends as soon as the external goal is obtained.

Malingering is established as separate from similar forms of excessive illness behaviour, such as somatization disorder, wherein symptoms are not deliberately falsified. Another disorder is factitious disorder, which lacks a desire for secondary, external gain. Both of these are recognised as diagnosable by the DSM-5. However, not all medical professionals are in agreement with these distinctions.