不活性気体 ふかっせいきたい Meanings Noun inert gas See also: 不活性ガス (ふかっせいガス). noble gas See also: 希ガス (きガス). Kanji 不 un-. Read as フ. 活 active. Read as カツ. 性 nature. Read as セイ. 気 spirit. Read as いき. 体 body. Read as タイ. Word lists Chemistry Jinuma: Japanese Dictionary · Word lists