Meaning & use
indefatigable
Last updated
Meaning
adjectivenot comparableformalapproving
Continuing to work or try hard without ever seeming to get tired or lose determination.
Grammar: Describes people or their efforts: an indefatigable volunteer.
Patterns
- indefatigable in something
- an indefatigable worker
The indefatigable nurse worked double shifts through the whole winter.
Her indefatigable curiosity led her to travel to forty countries.
He was indefatigable in his search for the missing dog.
Common combinations
- indefatigable energy
- The coach's indefatigable energy inspired the whole squad.
- indefatigable campaigner
- She was an indefatigable campaigner for clean water.
- indefatigable spirit
- The team showed an indefatigable spirit in defeat.
- indefatigable worker
- He is an indefatigable worker who answers emails at dawn.
- indefatigable in pursuit of
- Indefatigable in pursuit of the truth, the reporter kept digging.
Synonyms and how they differ
- tireless
- Tireless is the plainer, everyday equivalent, while indefatigable sounds more formal and emphatic.
- persistent
- Persistent stresses refusing to give up, but does not suggest the lack of tiredness indefatigable does.
- untiring
- Untiring is close in meaning but less grand, often used for effort over a long period.
- relentless
- Relentless can sound harsh or merciless, whereas indefatigable is admiring.
Opposites
Word family
- indefatigably adverb
- in a never-tiring way
- fatigue noun
- extreme tiredness
- fatigable adjective
- easily tired (rare)
- indefatigability noun
- the quality of never tiring
Commonly confused: indefatigable or indefinite?
indefatigable vs indefinite
Indefinite means not clearly limited or defined, while indefatigable means never tired; the shared start of the words is misleading.
Practice
Despite years of setbacks, the ___ researcher kept testing new ideas.
Choose one answer.
Indefatigable means never tiring. Indifferent means not caring, which would clash with someone who keeps trying.
Make it your own
Write a sentence using “indefatigable”, then check it and compare it with the examples above.