hal·lu·ci·na·tion 
/həˌlu:səˈneɪʃən/ noun
plural hal·lu·ci·na·tions /həˌlu:səˈneɪʃən/ noun [count] : something (such as an image, a sound, or a smell) that seems real but does not really exist and that is usually caused by mental illness or the effect of a drug
▪ He could not tell if what he was seeing was real or if it was a hallucination. ▪ He has been having hallucinations due to the medication.
▪ He could not tell if what he was seeing was real or if it was a hallucination. ▪ He has been having hallucinations due to the medication.
— hal·lu·ci·na·to·ry /həˈlu:sənəˌtori, Brit həˈlu:sənətri/ adjective
▪ hallucinatory drugs [=drugs that cause hallucinations] ▪ hallucinatory images
/həˈlu:sənəˌtori, Brit həˈlu:sənətri/ adjective ▪ hallucinatory drugs [=drugs that cause hallucinations] ▪ hallucinatory images
