insect
晜 is a rare kanji whose given meaning is 'insect'. Its standalone meaning is unclear and may be limited to this single gloss.
The historical development of 晜 is uncertain. It visually combines 日 (sun) and 弟 (younger brother), but the connection to 'insect' is not clear from these components.
Picture a sun-loving insect that crawls out when the sun is high, like a younger brother following the sun.
For コン, imagine a con artist insect that tricks other bugs: con -> コン.