(medicine) A pathological condition caused by oxygen deficiency at high altitudes; symptoms include shortness of breath, nausea, and nosebleed.

(medicine) Early morning nausea and vomiting as a symptom of pregnancy.

Alternative form of junk sick

(slang) Experiencing the nausea sometimes suffered by the user of a narcotic the following day, or after the effects of the drug begin to wear off, often with flulike symptoms.

(simile) Very ill.

(Canada, US) Used other than figuratively or idiomatically: see get, sick. / (euphemistic) To vomit.

(medicine) Altitude sickness.

A paid personal day intended to be used due to illness either for recuperation or medical treatment.

(archaic) Epilepsy.

Paid absence from work specifically to recover from illness.