Association to indicate synonyms

Rails
1

Which is the better way to indicating synonyms into a table? But I’d
get all those synonyms together to the main table. Althought if is
choosed a synonym I’d that it were directed to the object of the main
table.

I don’t know if a polymorphic association could be helpful in this
case. Any help please?

create_table :words do |t|
t.string :name
t.string :synonym # All synonyms of that word, if any (separated by
‘/’)
end

or

create_table :words do |t|
t.string :name

has_many :synonyms
end

create_table :synonyms do |t|
t.string :name

belong_to :words
end