| Noun | 1. | bummer - an experience that is irritating or frustrating or disappointing; "having to stand in line so long was a real bummer" annoyance, botheration, irritation, vexation - the psychological state of being irritated or annoyed |
| 2. | bummer - a bad reaction to a hallucinogenic drug effect - a symptom caused by an illness or a drug; "the effects of sleep loss"; "the effect of the anesthetic" |