Antonyms for "chances upon" include words such as avoid, ignore, overlook, neglect, and miss. These words suggest a lack of opportunity or unwillingness to take advantage of it when presented. Other antonyms may include premeditated, deliberate, or planned, which indicate a specific intention or purposeful action. While "chances upon" connotes a sense of serendipity or luck, its antonyms suggest a more deliberate approach to achieving a desired outcome. Understanding antonyms can help to enhance vocabulary and communication skills, allowing us to convey our thoughts and ideas with greater precision and nuance.