The opposite or the negative aspect of an adjective can be formed in a number of ways.

One way, of course, is to find an adjective to mean the opposite — an antonym. The opposite of beautiful is ugly, the opposite of tall is short. A thesaurus can help you find an appropriate opposite. Another way to form the opposite of an adjective is with a number of prefixes. The opposite of fortunate is unfortunate, the opposite of prudent is imprudent, the opposite of considerate is inconsiderate, the opposite of honourable is dishonourable, the opposite of alcoholic is non-alcoholic, the opposite of being properly filed is misfiled. If you are not sure of the spelling of adjectives modified in this way by prefixes (or which is the appropriate prefix), you will have to consult a dictionary, as the rules for the selection of a prefix are complex and too shifty to be trusted. The meaning itself can be tricky; for instance, flammable and inflammable mean the same thing.

A third means for creating the opposite of an adjective is to combine it with less or least to create a comparison which points in the opposite direction. Interesting shades of meaning and tone become available with this usage. It is kinder to say that "This is the least beautiful city in the state." than it is to say that "This is the ugliest city in the state." (It also has a slightly different meaning.) A candidate for a job can still be worthy and yet be "less worthy of consideration" than another candidate. It's probably not a good idea to use this construction with an adjective that is already a negative: "He is less unlucky than his brother," although that is not the same thing as saying he is luckier than his brother. Use the comparative less when the comparison is between two things or people; use the superlative least when the comparison is among many things or people.

  • My mother is less patient than my father.
  • Of all the new sitcoms, this is my least favourite show.