0 an occasion when the levels of sugar in someone's blood become dangerously low and they feel ill and may eventually become unconscious:
1 a syringe (= hollow needle) used to inject drugs under somoene's skin. It is short for hypodermic syringe:
He had never previously had a hypo.
Her hypos came on without much warning.
He twisted the hypo, separating the empty, rectangular syringe from the sharp, steel tip.
He snapped the Tunnel into the hypo and jabbed the needle into his hand.
Depressed patients are often characterized as having abnormal levels of ' arousal ', be it hypo- or hyper-arousal.