(inorganic chemistry) The sum of calcium and magnesium ion concentrations in water, normally expressed in mmol/L

plural of water hardness

Alternative spelling of blowhard

(colloquial, countable) Difficulties; a difficult time; trouble. / (colloquial, uncountable) A prison term.

Alternative spelling of hard sell

plural of try-hard

A type of pronunciation change required when speaking certain Celtic languages.

To connect components by means of permanent electrical wires. / (computing) To implement a feature in hardware rather than in software so that it cannot easily be changed.

plural of hard hat

A technical skill, not one that is interpersonal.