So, basically, withholding information is not the same thing as lying, but depending on the situation, you will have to decide whether it is better to withhold the information or not.
HCH may refer to: Hampton Court House, an independent school in Surrey, UK. Hexachlorocyclohexane, a group of chemical compounds. Holmes Chapel railway station (National Rail station code), in Cheshire, England.
Hydrochlorothiazide (abbreviated HCTZ, HCT, or HZT) is a diuretic medication often used to treat high blood pressure and swelling due to fluid build up. Other uses include diabetes insipidus, renal tubular acidosis, and to decrease the risk of kidney stones in those with high calcium level in the urine. For high blood pressure it is often recommended as a first line treatment.