From Longman Dictionary of Contemporary Englishbe seeing thingsbe seeing thingsIMAGINEto imagine that you see someone or something which is not really there There’s no one there – you must be seeing things. → see
Examples from the Corpus
be seeing things• ""Did that man just wave at me?'' ""Of course not, you must be seeing things.''• And now he was seeing things.• How Rab sat, his weakened state: his first night out, and he thought to be seeing things.• The first time i spotted a puffin I thought I was seeing things.• Oh yes, he was seeing things all right.• I suggest that the mirror has severe distortions, and perhaps Harley is seeing things grossly out of proportion.• In fact, as Steves eventually came to realize, they were seeing things that often elude travelers who spend far more.• Thomas seemed to be seeing things through the wrong end of a telescope.• At only 18, Dundas will be seeing things through young and excited eyes and I wish him the best.• I thought I saw Patty arrive. I must be seeing things today. 