Diligent
Middle English: via Old French from Latin diligens, diligent- ‘assiduous’, from diligere ‘love, take delight in’.
wiktionary
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.
etymonline
diligent (adj.)
"constant in effort to accomplish what is undertaken," mid-14c., from Old French diligent (14c.) and directly from Latin diligentem (nominative diligens) "attentive, assiduous, careful," present-participle adjective from diligere "single out, value highly, esteem, prize, love; aspire to, be content with, appreciate," originally "to pick out, select," from dis- "apart" (see dis-) + legere "choose, gather," from PIE root *leg- (1) "to collect, gather," with derivatives meaning "to speak (to 'pick out words')." Related: Diligently.
