Antonyms are words that have meanings opposite to that of another word.   Antonyms are useful ways to learn new words, and learning a new word can be made easier and more interesting if you also learn its opposite and other words that describe both its opposite and its meaning. Antonyms are words that mean the opposite of other words.

types of antonyms

Gradable antonyms
These are words pairs which have a ‘more-less’ relationship and they lie on a continuous spectrum, at the opposite ends of ONE continuum. Gradable antonyms include pairs such as:
beautiful – ugly
fat – thin
big – small
fast – slow
hot – cold
healthy – sick
shallow – deep
These word pairs do not refer to an either-or relationship, but a more-less relation.

Complementary Antonyms
Complementary antonyms are pairs of absolute opposites: if you are one, you cannot be the other. One is by definition incompatible with the other.
open – close
dead – alive
hello – goodbye

Converse (Relational)Antonyms
Each word has a natural opposite and would not exist without the other.
dead – alive
true – false
male- female
parent – child
on – off
open – close

Antonyms are also created by adding a  prefix to the same word root:
mis
dis
dys
mal
in
un
are all prefixes one can affix to words to create antonyms:
philanthropist – misanthropist.
trust – mistrust
interest – disinterest
adapted – maladapted
sufficient – insufficient
decisive – indecisive

Antonyms are useful ways to learn new words, and learning a new word can be made easier and more interesting if you also learn its opposite and other words that describe both its opposite and its meaning.