空疎|くうそkuuso[1]atamadaka (head-high)

1. na-adjective, nounempty (e.g. argument); insubstantial; hollow; fruitless

• Synonym空虚くうきょWrittenWritten/formal prose. Covers emptiness and hollowness, including a sense of inner emptiness; broader in range than 「空疎」.
• Synonym虚しいむなしいNeutralStresses a feeling of emptiness or the futility of an effort or outcome, as in 「虚しい努力」.
• Related希薄きはくWrittenWritten/formal prose. Means thin or dilute, stressing low density or concentration, as in 「人間関係が希薄」.
• Related空からNeutralRead 「うろ」. A physical hollow such as a tree hollow; stresses an empty interior and is not used figuratively for hollow arguments.
• Related薄いうすいNeutralThe everyday word for thin or weak; very broad in range, as in 「内容が薄い」.
• Related無意味むいみNeutralMeans pointless or meaningless, stressing lack of value; the content need not be hollow, as in 「無意味な争い」.
• Related薄っぺらうすっぺらCasualColloquial. Thin or shallow, with a disparaging nuance, as in 「薄っぺらな人間」.
• Related薄弱はくじゃくWrittenWritten/formal prose. Means weak or flimsy, stressing unsoundness, as in 「意志薄弱」「根拠薄弱」.
• Related無意義むいぎWrittenWritten/formal prose and less frequently used; close to 「無意味」 in meaning.
• Related虚ろうつろWrittenWritten/formal prose. Hollow or blank, stressing a vacant look or expression, as in 「虚ろな目」.
• RelatedちゃちCasualColloquial. Cheap and shoddily made, mostly about workmanship, as in 「ちゃちなおもちゃ」.
• Antonym充実じゅうじつNeutralAntonym. Means full and substantial in content, the opposite of hollow, insubstantial 「空疎」.

In everyday speech say 「中身がない」 or 「薄っぺら」. 「空疎」 is for written prose describing arguments or content that sound fine but lack substance, as in 「空疎な議論」. For inner emptiness use 「空虚」 or 「虚しい」; for thin, weak content 「薄い」 or 「希薄」; for a blank look 「虚ろ」; for shoddy work 「ちゃち」.

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

1. 外見がいけんだけで内容ないようや実質じっしつが伴ともなわないこと。また、そのようなさま。