What does indefatigably mean?
Indefatigably is an adverb meaning with tireless energy, persistence, and determination. It describes a person, group, or activity that continues with remarkable stamina despite demanding conditions, repeated effort, or the passage of time. A teacher might be described as indefatigably patient, while a campaigner could continue indefatigably despite opposition and setbacks. The word is formal and strongly affirmative, suggesting endurance that does not visibly diminish. It is related to the adjective indefatigable, which describes someone or something incapable of becoming tired or worn down. Because the expression can sound admiring or elevated, it is especially common in journalism, biography, historical writing, and speeches. In ordinary conversation, a simpler term such as tirelessly, relentlessly, or unceasingly may be more natural, depending on the degree of formality intended.
adverbIn a way that shows tireless energy, persistence, and an ability to continue without weakening.
- With sustained energy and determination, especially in the face of difficult or prolonged work.
"She indefatigably campaigned for better public transport for more than a decade."
"The indefatigably patient teacher explained the difficult passage once again."
"The volunteers continued indefatigably despite the heat and their dwindling supplies."
Some people seem energized by the very challenges that would exhaust everyone else.
Reviewed by Deb Chak, Editor. AI-assisted content curated by RJS Tech Solutions LLP.
Where does indefatigably come from?
The adverb was formed from the adjective indefatigable, which entered English in the 17th century from French indefatigable and Latin indefatigabilis. Its Latin roots combine the negative prefix in- with fatigare, meaning “to tire” or “to exhaust.” The same Latin source underlies forms such as fatigue and fatigable.
Related word forms
How indefatigably is actually used
This is a formal or literary word with an emphatic, occasionally idealized tone. It often suggests not merely hard work but sustained effort without fatigue or loss of determination.
Easily confused with indefatigably
Indefatigable is the adjective describing someone or something that cannot become tired, while indefatigably is the adverb describing how they act.