demanding (adj.)

late 14c., demaunden, "ask questions, make inquiry," from Old French demander (12c.) "to request; to demand," from Latin demandare "entrust, charge with a commission" (in Medieval Latin, "to ask, request, demand"), from de- "completely" (see de-) + mandare "to order" (see mandate (n.)).

Meaning "ask for with insistence or urgency" is from early 15c., from Anglo-French legal use ("to ask for as a right"). Meaning "require as necessary or useful" is by 1748. Related: Demanded; demanding.