The antonyms for the term "cast around" would be to focus, narrow down, direct, pinpoint or zero in. It means to search thoroughly or inquire about something or someone. The opposite of this would be to have a clear and specific goal in mind that requires no need for extensive searching or exploring. In a situation where time is of the essence or the matter is urgent, focusing on the best solution rather than casting around for options may be the better route to take. Hence, by having a clear objective in mind, it will reduce confusion and lead to a more efficient process.