diligent

adjective

working hard
careful and attentive

Wiktionary

Pronunciation: /ˈdɪlɪdʒənt/

adj

Etymology: 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.

Performing with industrious concentration; hard-working and focused.
“Scientists are very diligent in their work.”