The antonyms for the phrase "considered closely" could be "ignored casually" or "dismissed carelessly." These antonyms suggest a lack of attention or interest in analyzing or studying something in detail. Other antonyms could include "perfunctory" or "superficial," indicating a cursory examination without much thought or depth. The opposite of "considered closely" could also be "taken at face value" or "accepted without question," indicating a simplistic approach rather than a rigorous exploration of a topic. Ultimately, the antonyms for "considered closely" all suggest a lack of careful consideration, critical analysis, or thorough examination of a subject.