tuss, cough] - an agent that relieves coughing Another common prefix that you should know is ( an- before a vowel or h) which means "not, without, deficient, or lacking." An analgesic [ an-, not + alg, pain] is a substance that relieves pain. Likewise an anodyne [" + -odyne, pain] is a pain reliever. Compare these two words with antalgesic. All three words mean the same thing.