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 (HCTZ) is a diuretic approved for controlling high blood pressure and reducing water retention (edema). Clinical studies have shown that this medicine can significantly lower both systolic and diastolic blood pressure.