Antonymy  is  the  semantic  relationship  that  exists  between  two  
(or  more)  words  that  have opposite meanings. The pairs of words 
which have opposite meanings are called antonyms. Antonymous  pairs  of 
 words  usually  belong  to  the  same  grammatical  category  (i.e., 
both elements are nouns, or both are adjectives, or both are verbs, and 
so on). They are said  to  share  almost  all  their  semantic  
features  except  one.  The  semantic  feature  that  they do  not  
share  is  present  in  one  member  of  the  pair  and  absent  in  
the  other.
There are three major types of antonyms:
a. Complementary  or  contradictory  antonyms
They  are  pairs  of  words  in  which  one member has a certain 
semantic property that the other member does not have (cf. Ly-ons,  
1977).  Therefore,  in  the  context(s)  in  which  one  member  is  
true,  the  other  member  cannot  be  true.
male/female
married/unmarried
complete/incomplete
alive/dead
present/absent
awake/asleep 
b. Relational  antonyms
They  are  pairs  of  words  in  which  the  presence  of  a  certain  
semantic property in one member implies the presence of another semantic
 property in the other member. In other words, the existence of one of 
the terms implies the existence of the other  term.
over/under
buy/sell
doctor/patient
teacher/pupil
stop/go
em-ployer/employee
taller/shorter
cheaper/more expensive.
c. Gradable or scalar antonyms
They are pairs of words that are contrasted with re-spect to their 
degree of possession of a certain semantic property. Each term 
represents or stands  for  an  end-point  (or  extreme)  on  a  scale  
(e.g., of  temperature,  size,  height,  beauty,  etc.); between those 
end-points there are other intermediate points (i.e., there is some 
mid-dle  ground)  (cf.  Godby  et  al.,  1982;  Lyons,  1977). 
hot/cold
big/small
tall/short
good/bad
strong/weak
beautiful/ugly
happy/sad
fast/slow
Antonyms may be:
(a) morphologically unrelated (i.e., one of the elements of the pair does not derive from the other)
good/bad,  high/low
(b)  morphologically  related (i.e.,  one  of  the  members  of  a  
pair  of  antonyms  is  derived  from  the  other  member  by  the  
addition   of   a   negative   word   or   an   affix)
good/not   good
friendly/unfriendly
likely/unlikely. 
(http://webdelprofesor.ula.ve/humanidades/azapata/materias/english_4/unit_1_semantic_relationships.pdf)
Lexemes like on and off, old and young, wide and narrow are pairs of antonyms. Antonyms are opposite in meaning, and when they occur as predicates of the same subject the predications are contradictory. Antonyms may be nouns like Communist and non-Communist or verbs such as advance and retreat, but antonymous pairs of adjectives are especially numerous.
English has various pairs of measure adjectives:
long - short
tall - short
high - low
wide - narrow
old - young
deep - shallow
old - new
thick - thin
Lexemes like on and off, old and young, wide and narrow are pairs of antonyms. Antonyms are opposite in meaning, and when they occur as predicates of the same subject the predications are contradictory. Antonyms may be nouns like Communist and non-Communist or verbs such as advance and retreat, but antonymous pairs of adjectives are especially numerous.
English has various pairs of measure adjectives:
long - short
tall - short
high - low
wide - narrow
old - young
deep - shallow
old - new
thick - thin
