Use the adjective significant to describe something that is important. Your "significant other" means the person who's most important in your life. A significant result in a scientific study is a result large enough to matter.

A less common meaning of significant is to describe something that has a special or hidden meaning. A significant smile can convey feelings or information without words. This adjective is from Latin significans, from significare "to signify," from signum "a sign, mark" plus facere "to make."

Definitions of significant
  1. adjective
    rich in significance or implication
    synonyms: meaning, pregnant
    having a meaning or purpose
  2. adjective
    important in effect or meaning
    “a significant change in tax laws”
    “a significant change in the Constitution”
    “a significant contribution”
    significant details”
    “statistically significant
    synonyms: important
    important, of import
    of great significance or value
    having a meaning or purpose
    of very great significance
    epoch-making, epochal
    highly significant or important especially bringing about or marking the beginning of a new development or era
    earthshaking, world-shaking, world-shattering
    sufficiently significant to affect the whole world
    evidential, evidentiary
    serving as or based on evidence
    fundamental, profound
    far-reaching and thoroughgoing in effect especially on the nature of something
    fairly large or important in effect; influential
    of outstanding significance
    noteworthy, remarkable
    worthy of notice
    probative, probatory
    tending to prove a particular proposition or to persuade you of the truth of an allegation
    effective; producing a desired effect
    portentous, prodigious
    of momentous or ominous significance
    see moresee less
    insignificant, unimportant
    devoid of importance, meaning, or force
    not important
    meaningless, nonmeaningful
    having no meaning or direction or purpose
    hole-and-corner, hole-in-corner
    relating to the peripheral and unimportant aspects of life
    flimsy, fragile, slight, tenuous, thin
    lacking substance or significance
    too small to make a significant difference
    having little importance
    superficial, trivial
    of little substance or significance
    show more antonyms...
  3. adjective
    fairly large
    synonyms: substantial
    large or relatively large in number or amount or extent or degree
  4. adjective
    too closely correlated to be attributed to chance and therefore indicating a systematic relation
    “the interaction effect is significant at the .01 level”
    “no significant difference was found”
    see moresee less
    attributable to chance
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