Vaporous means foggy, or made of gas. On a misty morning, the cool, vaporous air by the sea might send you back home for a raincoat.

In science, this adjective is used for gases, including the vaporous water detected in the atmosphere of a distant planet, or the invisible swirl of vaporous wax that hovers above a lit candle. When the air feels vaporous, it's either foggy or extremely humid. Something that seems to lack real substance can also be described this way, like your vaporous plan to bike across the U.S., quickly abandoned as you realized how difficult it would be.

Definitions of vaporous
  1. adjective
    resembling or characteristic of vapor
    vaporous clouds”
    synonyms: vaporific, vaporish, vapourific, vapourish, vapourous
    existing as or having characteristics of a gas
  2. adjective
    filled with vapor
    “a vaporous bog”
    synonyms: miasmal, miasmic, vapourous
    full of or covered with clouds
  3. adjective
    so thin as to transmit light
    vaporous silks”
    synonyms: cobwebby, diaphanous, filmy, gauze-like, gauzy, gossamer, see-through, sheer, transparent, vapourous
    of relatively small extent from one surface to the opposite or in cross section
Word Family

Test prep from the experts

Boost your test score with programs developed by’s experts.

  • Proven methods: Learn faster, remember longer with our scientific approach.
  • Personalized plan: We customize your experience to maximize your learning.
  • Strategic studying: Focus on the words that are most crucial for success.


  • Number of words: 500+
  • Duration: 8 weeks or less
  • Time: 1 hour / week


  • Number of words: 500+
  • Duration: 10 weeks or less
  • Time: 1 hour / week


  • Number of words: 700+
  • Duration: 10 weeks
  • Time: 1 hour / week