- hard-working
- industrious
- conscientious
- assiduous
- punctilious
- particular
- painstaking
- meticulous
- exacting
- rigorous
- thorough
- careful
- attentive
- sedulous
- intent
- heedful
- studious
- earnest
- persevering
- constant
- tenacious
- persistent
- zealous
- pertinacious
- committed
- dedicated
- active
- driven
- unflagging
- busy
- tireless
- untiring
- dogged
- indefatigable
- slogging
- plodding
- laborious
Example Sentences of Diligent
1. She is a diligent student always.
2. His diligent work paid off greatly.
3. They are diligent in their studies.
4. A diligent effort leads to success.