Intensive is a word that typically refers to a concentrated or thorough effort. Its antonyms, on the other hand, refer to a lack of focus or intensity. Some common antonyms for intensive include superficial, perfunctory, lackadaisical, cursory, and negligent. Superficial refers to something that is shallow, lacking depth or substance. Perfunctory suggests minimal effort put into something, just going through the motions without any real enthusiasm or engagement. Lackadaisical suggests a lack of enthusiasm or motivation, while cursory suggests something that is done quickly and without much attention to detail. Negligent refers to a complete lack of attention, carelessness or irresponsibility.