sprain /spɹeɪn/noun 1verb 1forms 3 noun1 •The act or result of spraining; lameness caused by spraining verb1 •To weaken, as a joint, ligament, or muscle, by sudden and excessive exertion, as by wrenching; to overstrain, or stretch injuriously, but without luxationHe sprained his knee after falling off the bicycle. formssprained · spraining · sprains