less
I
 /ˈlɛs/  adj   comparative form of little, 1
  : not so much : smaller in amount or number
   We need less talk and more work!
   She finished in less time than I did.
   Less detail is sometimes better than more detail.
   8 times 2 is less than 6 times 3.
   We made it there in less than six hours.
   The whole procedure takes less than five minutes.
   The illness affects less than one percent of the population.
  no less
    — used to suggest that something is surprising or impressive
    He insists on being driven to the airport, and in a limousine no less! [=it is surprising that he insists on being driven in a limousine]
    She was contacted by the president, no less!
    The plan was approved by no less (of) an authority than the president himself.
   
  no less than
   : at least
    — used to suggest that a number or amount is surprisingly large
    No less than half the students failed the test.
    She has had no less than [=no fewer than] a dozen job offers.
   
   usage
   The adjectives less and fewer have similar meanings but are used in slightly different ways. Fewer is used with nouns that can be counted.
    classrooms with fewer students
    They have fewer than three children.
    Less is usually used with nouns that cannot be counted.
    He makes less money than she does.
    The new model uses less power.
    But less is also more likely than fewer to be used with count nouns that refer to distances and amounts of money.
    an investment of less than $2,000
    It's less than 100 miles away.
    Less is also used in mathematical expressions and in certain phrases.
    an angle of less than 180 degrees
    Write it in 25 words or less.
    It is also used instead of fewer with other sorts of plural nouns, although many people still consider this use incorrect.
    Less than 10 people showed up. = Fewer than 10 people showed up.
   
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II
  adv   comparative form of little, 2
  : not so much : to a smaller extent or degree
   This test seemed much less difficult than the last one.
   Which test is the less difficult of the two?
   The test is no less difficult for being shorter. [=even though the test is shorter, it is not easier]
   Do you have another one that's less expensive?
   a less likely possibility
   She visits much/far less often than she used to.
   They're focusing more on quality and less on quantity.
   I like this one (a little) less than the other.
   Their band is less concerned with making music than with making money.
   The cost is much/far less (of) a problem than we thought it would be.
  in less than no time
    informal   : very soon
    If we get started now, we'll be finished in less than no time.
  less and less
   : in a way that is gradually smaller, weaker, or less common
    The medicine becomes less and less [=decreasingly] effective over time.
    We see them less and less each year. = We see them less and less frequently/often each year.
  less than
   : not completely or not at all
    She was less than happy with the results. [=she was not entirely happy or she was unhappy]
    He was less than honest in his replies. [=he was not completely honest or he was very dishonest]
  more or less — see more, 2
  much less ( or chiefly Brit   still less)
    — used after a negative statement to say that something is even less likely or possible than the thing previously mentioned
    I don't eat eggs, much less meat.
    He can't run a mile, much less complete a marathon.
   
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III
  pronoun  
  1 : a smaller number or amount
   We've learned to make do with less. [=to survive with less money, fewer possessions, etc.]
   He's trying to save more and spend less.
   I have less than you do.
   I read much/far/even less of the second book than of the first.
   I seem to save less each year.
   We had exactly one day to get the job done–no more, no less.
   Less is sometimes better than more.
   Regarding his recent behavior, perhaps the less said, the better. [=his recent behavior has been so bad that it is better to not say anything about it]
  2 : something that is smaller or less important than another thing
   You're lucky you didn't lose your job for swearing at your boss. People have been fired for less (than that).
  could/couldn't care less — see care, 2
  less and less
   : an amount that becomes gradually smaller
    I seem to save less and less each year.
    We see less and less of them each year.
  nothing less than — see nothing, 2
  think less of — see think, 1
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IV
  prep  
  : after taking away or subtracting (something)
   the regular price less [=minus] a discount
   We earned two hundred dollars, less travel expenses.