Something that is insubstantial is not large, solid, or strong.
例句
Mars has an insubstantial atmosphere, consisting almost entirely of carbon dioxide...火星的大氣層極其稀薄,幾乎全部由二氧化碳構成。Her limbs were insubstantial, almost transparent.她的四肢非常纖細,幾乎是透明的。
英漢詞典釋義
adj.
非實在的
an insubstantial semblance不實在的表象an insubstantial mirage on the horizon地平線上虛幻的海市蜃樓
英英詞典釋義
Adjective
1. lacking material form or substance; unreal;
"as insubstantial as a dream""an insubstantial mirage on the horizon"