• 淡あわい — pale; faint; light (color/flavor)
• 淡色たんしょく — light color; pastel
• 冷淡れいたん — cool; indifferent
• 淡泊たんぱく — plain; simple; not rich (flavor/feeling)
• 清淡せいたん — clear and light; understated
• 淡水たんすい — fresh water (opposite of seawater)

A phono-semantic character: 氵 marks “water,” while 炎 (phonetic) gives the reading タン and suggests something thinned or attenuated. The core nuance is “light” or “not dense” — a pale color, mild taste, or cool feeling. This contrasts naturally with 濃 (“dense, rich”).