• 微妙びみょう — subtle; delicate
• 微笑びしょう — faint smile
• 微風そよかぜ — gentle breeze
• 微弱びじゃく — weakness; faintness
• 微光びこう — faint light

微 combines the radical 彳（ぎょうにんべん）meaning “step” or “movement” with a phonetic part that gives the reading ビ. The whole kanji suggests something so small or subtle it can hardly be seen — a faint step, a slight trace. This is why it came to mean delicate, faint, or subtle.