Meaning

adjective quietly and steadily persevering especially in detail or exactness

adjective characterized by care and perseverance in carrying out tasks

originFrom Middle English diligent, from Old French diligent, from Latin dīligēns (“careful, attentive, diligent”), present participle of dīligō (“to love, esteem much”, literally “to choose, select”), from dī-, dis- (“apart”) + legō (“to choose”); see elect and select.

Etymology from Wiktionary, CC BY-SA 3.0