What does anergic mean?
Anergic is an adjective used chiefly in medicine and psychology to describe a marked lack of energy or responsiveness. In its everyday clinical sense, it characterizes patients who are profoundly listless and fatigued, as in 'anergic depression', a form of depressive illness dominated by exhaustion and inertia rather than sadness. In immunology, the word has a second, more specialized meaning: an anergic patient's immune system fails to react to antigens, which can cause skin tests such as the tuberculin test to yield false negatives despite infection. The word derives from the Greek an- ('without') combined with ergon ('work'), literally meaning 'without work' or 'inactive'. Because it is precise and technical, anergic rarely appears in casual conversation, where speakers prefer simpler terms like tired or lethargic; yet it remains valuable in clinical writing, where distinguishing physical exhaustion from a genuine failure of biological response can matter greatly.
Lacking energy or vitality; characterized by inactivity or reduced capacity for action.
"The anergic patient spent most days in bed, drained of any impulse to move."
Common in psychiatric descriptions, especially 'anergic depression'.
(Immunology) Unresponsive to an antigen or other immune stimulus.
"An anergic response to the skin test suggested impaired T-cell function."
In medicine, 'anergic' can describe the opposite of what you'd fear from an allergy: an immune system so unresponsive it fails to react at all.
Reviewed by Deb Chak, Editor. AI-assisted content curated by RJS Tech Solutions LLP.
Etymology of anergic
Anergic comes from the Greek anergēs, formed from the prefix an- ('without') and ergon ('work'), hence 'inactive' or 'without work'. It entered English through scientific and medical vocabulary in the nineteenth century, alongside related terms built on the same root such as energy, synergy, and allergy. The noun form anergy denotes the condition itself, particularly the immunological failure to respond to an antigen.
Related word forms
How anergic is actually used
Primarily a formal or technical term found in medical and psychological contexts; 'anergic depression' is an established psychiatric descriptor. In everyday speech, words like 'lethargic' or 'worn out' are far more common.
Easily confused with anergic
Allergic describes a hypersensitive immune reaction to a substance, whereas anergic describes an absent or weakened response, whether of the body or the mind.