quick, prompt, ready, apt mean able to respond without delay or hesitation or indicative of such ability. quick stresses instancy of response and is likely to connote native rather than acquired power.
If you are prompt to do something, you do it without delay or you are not late. You have been so prompt in carrying out all these commissions. We didn't worry because they were always so prompt with their rental payment.
performed at once or without delay: a prompt reply. quick to act or respond: [be + ~] was prompt in answering our phone call. [~ + to + verb] They were prompt to deny the allegations.
1. done, performed, delivered, etc., at once or without delay: a prompt reply.