[ ɪ'l(j)u:ʒ(ə)n ]
■ noun a false idea or belief.
↘a deceptive appearance or impression.
↘a false or unreal perception.
Phrases
be under the ~ that believe mistakenly that.
Derivatives
~al adjective
~ary adjective
Origin
ME: via OFr. from L. illusio(n-) , from illudere 'to mock'.