hypo

noun

1. Melancholy; a fit of ‘hypochondria’; a morbid depression.“1837 Abraham Lincoln: Tell your sister I dont want to hear any more about selling out and moving. That gives me the hypo whenever I think of it. (Letter to Mary S. Owens, May 7. 1837, Collected Works of Abraham Lincoln. Volume 1.”
2. A hypochondriac.
3. Sodium thiosulphate, a photographic fixing agent.
4. A hypoglycaemia attack in a person with diabetes.