Diligent means working with steady careful effort. A diligent student, diligent research, diligently checked.
It praises consistency rather than brilliance, and it is the standard word in references for somebody reliable. Due diligence is the formal investigation done before a deal or an appointment, and it is a defined legal duty in many contexts. Note diligence; and that the Latin behind it means to esteem or choose carefully, which is a much warmer origin than steady plodding.
1adjectivediligentWorking with steady careful effort.
“She's a diligent student who checks every answer twice.”
synonyms: assiduous, conscientious
diligent is a quality of careful effort.
Also accepted in games: hardworking
Latin diligens is the present participle of diligere, to esteem or love — dis plus legere, to choose. Elect, intelligent and legible come from the same choosing.
Proto-Indo-European
*leǵ-
Latin
dīligēns — careful, attentive, diligent
Old French
diligent
Middle English
diligent
English, today
diligent
Built from
From 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