The kanji character 怪怪 primarily conveys the idea of something strange, mysterious, or uncanny. It can imply a sense of unusualness, something out of the ordinary, or even something suspicious or frightening. It often refers to things that are not easily understood or explained, things that evoke a feeling of wonder or fear.

・On-yomi (音読み): カイ ・Kun-yomi (訓読み): あや（しい）, あや（しむ）

⚫︎ 怪しい人 Translation: Suspicious person ⚫︎ 怪奇現象 Translation: Strange phenomenon; paranormal activity ⚫︎ 妖怪 Translation: Monster; specter; goblin; apparition

The kanji 怪怪 is a phono-semantic compound. It is formed by combining the radical 忄 (りっしんべん), which represents the heart or mind, and the phonetic component 圭, which provides the sound and hints at the meaning. The radical suggests the emotion or feeling associated with something strange, and the phonetic component 圭 might be used to indicate a state of being "unsettled" or "uncertain." The original meaning was likely connected to the feeling of being surprised or perplexed. Over time, it broadened to include the concepts of strangeness, mystery, and the uncanny.