硬い【かたい】
hard, solid, tough, stiff, tight, wooden, unpolished (e.g. writing), strong, firm (not viscous or easily moved), safe, steady, honest, steadfast, obstinate, stubborn, bookish, formal, stuffy
硬貨【こうか】
coin, hard currency
硬さ【かたさ】
firmness, hardness, stiffness, honesty
硬化【こうか】
hardening, vulcanization, vulcanisation, sclerosis, curing, hardening (of attitude, stance, etc.), stiffening, toughening, upturn (in the market), firming up
強硬【きょうこう】
firm, strong, unbending, unyielding, uncompromising, stubborn, tough, hard-line
硬派【こうは】
hard-liners, diehards, hawks, (young) man with traditionally masculine interests, tough boy, man's man, hard news, reporter who covers political and economic affairs, strait-laced type (with respect to relationships), bullish traders
硬度【こうど】
hardness, solidity
硬直【こうちょく】
stiffening, rigidity, rigor, stiffness, ossification, petrification
肝硬変【かんこうへん】
cirrhosis (of the liver)
動脈硬化【どうみゃくこうか】
arteriosclerosis, hardening of the arteries
硬質【こうしつ】
hardness, stiffness
硬式【こうしき】
hard (esp. of hardball, tennis, etc.)
硬軟【こうなん】
hardness and softness, hard line and moderate line
硬筆【こうひつ】
pen or pencil
硬骨【こうこつ】
bone, firmness (of character), backbone, unyielding spirit