Webster's Revised Unabridged Dictionary · 1913

Diligent

Diligent , adjective

[French diligent, Latin diligens, -entis, present participle of diligere, dilectum, to esteem highly, prefer; di- = dis- + legere to choose. See Legend.]

1.
Prosecuted with careful attention and effort; careful; painstaking; not careless or negligent.
The judges shall make diligent inquisition. — Deut. xix. 18
2.
Interestedly and perseveringly attentive; steady and earnest in application to a subject or pursuit; assiduous; industrious.
Seest thou a man diligent in his business? he shall stand before kings. — Bible (KJV) - Proverb xxii. 29
Diligent cultivation of elegant literature. — Prescott