Antonyms for the phrase "most low profile" could include "most high profile," "most visible," or "most prominent." These antonyms suggest a person or thing that attracts attention, stands out, or is well-known. Alternatively, "most outspoken," "most outgoing," or "most extroverted" could also be considered antonyms, as these describe individuals who are the opposite of reserved or inconspicuous. In short, antonyms for "most low profile" would refer to a person, place or thing that is significant, noticeable or vocal - the exact opposite of someone or something that flies under the radar.