The prefix hyper- means over, too much or increased. Hypertension is blood pressure that is too high, hyperglycaemia is blood sugar that is too high, hyperthyroidism is an overactive thyroid. Its counterpart is hypo-.
Greek hypér = over, above
Over-, increased
hyper-
Prefixes change the basic meaning of a term systematically. The most important pairs are hyper- and hypo-, macro- and micro-, poly- and oligo-, tachy- and brady-.
A single letter can decide the diagnosis: hyperkalaemia and hypokalaemia are opposite conditions, and both are life-threatening.
Free and no obligation.