" unsubstantial "

1: not composed of matter;

  * e.g., " ... as thin and unsubstantial as the wind "

•  Synonyms : 

•  bodiless,

•  ethereal,

•  formless,

•  immaterial,

•  incorporeal,

•  insubstantial,

•  nonmaterial,

•  nonphysical,

•  spiritual,

•  unbodied

•  Antonyms : 

•  bodily,

•  corporeal,

•  material,

•  physical,

•  substantial

2: being of a material lacking in sturdiness or substance;

  * e.g., " ... unsubstantial wisps of lace "

•  Synonyms : 

•  cobwebby,

•  filmy,

•  flimsy,

•  frothy,

•  gauzy,

•  gossamer,

•  gossamery,

•  insubstantial,

•  sleazy

•  Antonyms : 

•  sturdy,

•  substantial

3: lacking bodily strength;

  * e.g., " ... an unsubstantial child who was unfit to play sports of any kind "

•  Synonyms : 

•  asthenic,

•  debilitated,

•  delicate,

•  down-and-out,

•  effete,

•  enervated,

•  enfeebled,

•  faint,

•  feeble,

•  frail,

•  infirm,

•  languid,

•  low,

•  prostrate,

•  prostrated,

•  sapped,

•  slight,

•  soft,

•  softened,

•  tender,

•  wasted,

•  weak,

•  weakened,

•  wimpish,

•  wimpy

•  Antonyms : 

•  mighty,

•  powerful,

•  rugged,

•  stalwart,

•  stout,

•  strong