空虚|くうきょkuukyo[1]atamadaka (head-high)

1. noun, na-adjectiveemptiness; hollowness; vacancy; void
   神かみに向むかって話はなしかけてみてもそこにあるのは空虚くうきょのみ。↗

   I talk to God but the sky is empty.
2. noun, na-adjectiveinanity; pointlessness; meaninglessness

• Synonym空からNeutralPhysically empty with nothing inside, as in 「空の箱」; leans toward containers and lacks the sense of inner hollowness that 「空虚」 carries.
• Synonym空っぽからっぽCasualColloquial for being completely empty, as in 「頭が空っぽ」; like 「空虚」, it can also express inner emptiness, as in 「心が空っぽ」.
• Synonym空疎くうそWrittenWritten/formal prose for hollow content, as in 「空疎な議論」; leans toward arguments or words lacking substance rather than inner emptiness.
• Synonym虚しいむなしいNeutralAn adjective for futile, empty feelings with a melancholy tinge, as in 「虚しい努力」; leans toward emotion rather than the state of being empty.
• Related空白くうはくNeutralA blank or gap, as in 「記憶の空白」; leans toward a missing piece, and can figuratively mean something missing in the heart, as in 「心の空白」.
• RelatedがらんどうWrittenWritten/formal word for rooms or buildings standing bare and empty, as in 「がらんどうの部屋」; can also picture inner emptiness, more concrete and vivid than 「空虚」.
• RelatedエンプティーNeutralLoanword meaning empty, mostly seen on gauges or displays showing 「E」; rare in everyday speech.
• Relatedがら空きがらあきCasualColloquial for seats or venues being nearly deserted, as in 「電車ががら空き」.
• Antonym充実じゅうじつNeutralAntonym: fullness or a fulfilling state, the direct opposite of the hollow emptiness of 「空虚」.
• Antonym豊かゆたかNeutralAntonym: rich or abundant, as in 「心が豊か」; the opposite of 「空虚」.

For things that are simply empty, use 「空」 or 「空っぽ」. For inner hollowness or a life or words lacking substance, use 「空虚」, as in 「空虚な毎日」「心の空虚」. For futility, use 「虚しい」; for the opposite, 「充実」.

Usage comparisons are AI-assisted and cross-checked by multiple models; for study reference only

1. 中身なかみに何なんもないこと。
2. 実質的じっしつてきな内容ないようや価値かちのないこと。