奇怪 (qí guài) is an adjective meaning 'strange', 'odd', or 'unusual'. It combines two characters, both of which individually carry meanings related to the unfamiliar: 奇 (qí) means 'rare', 'unusual', or 'marvelous', while 怪 (guài) means 'strange', 'odd', or 'to blame' — together they reinforce a sense of something defying expectation or common understanding. Unlike some adjectives in Chinese, 奇怪 can stand alone as a predicate without needing 很 or other degree adverbs, though it’s often used with them for emphasis.

This word is commonly used in spoken and written Mandarin to express mild surprise, curiosity, or mild disapproval about unexpected behavior, situations, or appearances. It frequently appears in questions (e.g., '怎么这么奇怪？') or statements expressing puzzlement. While not inherently negative, its tone depends on context — it may signal harmless curiosity ('That cat’s behavior is strange') or subtle concern ('His sudden silence feels strange'). It rarely describes physical objects in isolation without implied reaction or judgment.